Compounds, compositions, and methods of increasing CFTR activity

ABSTRACT

The present disclosure features compounds such as those having the Formulae (I) and (II), which can increase cystic fibrosis transmembrane conductance regulator (CFTR) activity as measured in human bronchial epithelial (hBE) cells. The present disclosure also features methods of treating a condition associated with decreased CFTR activity or a condition associated with a dysfunction of proteostasis comprising administering to a subject an effective amount of a disclosed compound, such as a compound of Formula (I) or (II).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. § 371 ofPCT/US2016/043835, filed Jul. 25, 2016, which claims the benefit of, andpriority to, U.S. provisional application Ser. No. 62/196,841, filedJul. 24, 2015; 62/199,672, filed Jul. 31, 2015; 62/271,177, filed Dec.22, 2015; 62/271,812, filed Dec. 28, 2015; and 62/277,595, filed Jan.12, 2016; the contents of each of which is hereby incorporated byreference herein in its entirety.

BACKGROUND

Cells normally maintain a balance between protein synthesis, folding,trafficking, aggregation, and degradation, referred to as proteinhomeostasis, utilizing sensors and networks of pathways (Sitia et al.,Nature 426: 891-894, 2003; Ron et al., Nat Rev Mol Cell Biol 8: 519-529,2007). The cellular maintenance of protein homeostasis, or proteostasis,refers to controlling the conformation, binding interactions, locationand concentration of individual proteins making up the proteome. Proteinfolding in vivo is accomplished through interactions between the foldingpolypeptide chain and macromolecular cellular components, includingmultiple classes of chaperones and folding enzymes, which minimizeaggregation (Wiseman et al., Cell 131: 809-821, 2007). Whether a givenprotein folds in a certain cell type depends on the distribution,concentration, and subcellular localization of chaperones, foldingenzymes, metabolites and the like. Cystic fibrosis and other maladies ofprotein misfolding arise as a result of an imbalance in the capacity ofthe protein homeostasis (proteostasis) environment to handle the reducedenergetic stability of misfolded, mutated proteins that are critical fornormal physiology (Balch et al., Science 319, 916-9 (2008); Powers, etal., Annu Rev Biochem 78, 959-91 (2009); Hutt et al., FEBS Lett 583,2639-46 (2009)).

Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosistransmembrane conductance regulator (CFTR) gene which encodes amulti-membrane spanning epithelial chloride channel (Riordan et al.,Annu Rev Biochem 77, 701-26 (2008)). Approximately ninety percent ofpatients have a deletion of phenylalanine (Phe) 508 (ΔF508) on at leastone allele. This mutation results in disruption of the energetics of theprotein fold leading to degradation of CFTR in the endoplasmic reticulum(ER). The ΔF508 mutation is thus associated with defective folding andtrafficking, as well as enhanced degradation of the mutant CFTR protein(Qu et al., J Biol Chem 272, 15739-44 (1997)). The loss of a functionalCFTR channel at the plasma membrane disrupts ionic homeostasis (Cl⁻,Na⁺, HCO₃ ⁻) and airway surface hydration leading to reduced lungfunction (Riordan et al.). Reduced periciliary liquid volume andincreased mucus viscosity impede mucociliary clearance resulting inchronic infection and inflammation, phenotypic hallmarks of CF disease(Boucher, J Intern Med 261, 5-16 (2007)). In addition to respiratorydysfunction, ΔF508 CFTR also impacts the normal function of additionalorgans (pancreas, intestine, gall bladder), suggesting that theloss-of-function impacts multiple downstream pathways that will requirecorrection.

In addition to cystic fibrosis, mutations in the CFTR gene and/or theactivity of the CFTR channel has also been implicated in otherconditions, including for example, congenital bilateral absence of vasdeferens (CBAVD), acute, recurrent, or chronic pancreatitis,disseminated bronchiectasis, asthma, allergic pulmonary aspergillosis,smoking-related lung diseases, such as chronic obstructive pulmonarydisease (COPD), dry eye disease, Sjogren's syndrome and chronicsinusitis, (Sloane et al. (2012), PLoS ONE 7(6):e39809.doi:10.1371/journal. pone.0039809; Bombieri et al. (2011), J CystFibros. 2011 Jun. 10 Suppl 2:S86-102; (Albert et al. (2008). ClinicalRespiratory Medicine, Third Ed., Mosby Inc.; Levin et al. (2005), InvestOphthalmol Vis Sci., 46(4):1428-34; Froussard (2007), Pancreas 35(1):94-5).

There remains a need in the art for compounds, compositions and methodsof increasing CFTR activity as well as for methods of treating CF, otherCFTR-related diseases, and other maladies of protein misfolding.

SUMMARY

The present disclosure is based, in part, on the discovery thatdisclosed compounds such as those having the Formulae (I) and (II)increase cystic fibrosis transmembrane conductance regulator (CFTR)activity as measured in human bronchial epithelial (hBE) cells.

In an embodiment, this disclosure is at least partially directed to amethod of enhancing cystic fibrosis transmembrane conductance regulator(CFTR) activity in a subject in need thereof is provided, which includesadministering to said subject an effective amount of a compound havingthe formula (I) or (II) as disclosed herein.

In additional embodiments, a method of enhancing (e.g., increasing)cystic fibrosis transmembrane conductance regulator (CFTR) activity in asubject in need thereof is provided comprising administering to saidsubject an effective amount of a compound of Formula (I) and (II).

In certain of these embodiments, the activity of one or more (e.g., oneor two) mutant CFTRs (e.g., ΔF508, S549N, G542X, G551D, R117H, N1303K,W1282X, R553X, 621+1G>T, 1717−1G>A, 3849+10 kbC>T, 2789+5G>A, 3120+1G>A,I507del, R1162X, 1898+1G>A, 3659delC, G85E, D1152H, R560T, R347P,2184insA, A455E, R334W, Q493X, and 2184delA CFTR) is enhanced (e.g.,increased). In certain embodiments, ΔF508 CFTR activity is enhanced(e.g., increased). In other embodiments, the activities of two mutantCFTRs (e.g., ΔF508 and G551D; ΔF508 and A455E; or G542X and Δ508F) areenhanced (e.g., increased).

In certain of these embodiments, the subject (e.g., a human patient) issuffering from a disease associated with decreased CFTR activity (e.g.,cystic fibrosis, congenital bilateral absence of vas deferens (CBAVD),acute, recurrent, or chronic pancreatitis, disseminated bronchiectasis,asthma, allergic pulmonary aspergillosis, chronic obstructive pulmonarydisease (COPD), chronic sinusitis, dry eye disease, protein Cdeficiency, A-β-lipoproteinemia, lysosomal storage disease, type 1chylomicronemia, mild pulmonary disease, lipid processing deficiencies,type 1 hereditary angioedema, coagulation-fibrinolyis, hereditaryhemochromatosis, CFTR-related metabolic syndrome, chronic bronchitis,constipation, pancreatic insufficiency, hereditary emphysema, Sjogren'ssyndrome, familial hypercholesterolemia, I-cell disease/pseudo-Hurler,mucopolysaccharidoses, Sandhof/Tay-Sachs, Crigler-Najjar type II,polyendocrinopathy/hyperinsulemia, Diabetes mellitus, Laron dwarfism,myleoperoxidase deficiency, primary hypoparathyroidism, melanoma,glycanosis CDG type 1, congenital hyperthyroidism, osteogenesisimperfecta, hereditary hypofibrinogenemia, ACT deficiency, Diabetesinsipidus (DI), neurophyseal DI, nephrogenic DI, Charcot-Marie Toothsyndrome, Perlizaeus-Merzbacher disease, Alzheimer's disease,Parkinson's disease, amyotrophic lateral sclerosis, progressivesupranuclear palsy, Pick's disease, Huntington's disease,spinocerebellar ataxia type I, spinal and bulbar muscular atrophy,dentatorubral pallidoluysian, myotonic dystrophy, hereditaryCreutzfeldt-Jakob disease (due to prion protein processing defect),Fabry disease, and Straussler-Scheinker syndrome). In certainembodiments, the disease is cystic fibrosis.

In yet additional aspects, the disclosure is directed to treating apatient suffering from cystic fibrosis comprising administering to saidpatient an effective amount of a disclosed compound (e.g., a compoundprovided herein, .e.g., Formulas I, and II (e.g., a compound of Table 1)and optionally, administering to said patient a) CFTR potentiator and/orb) a CFTR corrector.

In certain embodiments, methods can include: administering to thepatient an effective amount of a disclosed compound; and administeringivacaftor. In certain of these embodiments, methods can further includeadministering VX-661 or lumacaftor. In another aspect, this disclosureprovides methods of treating a patient with F508del homozygous CFTRmutation, comprising: administering to the patient an effective amountof a disclosed compound; administering ivacaftor; and/or administeringlumacaftor or VX661. In a further aspect, this disclosure providesmethods of treating a patient with a G542X class I CFTR mutation,comprising: administering to the patient an effective amount of adisclosed compound; and optionally administering NB124. In still anotheraspect, this disclosure provides methods of treating a patient with aA455E Class V CFTR mutation, comprising: administering to the patient aneffective amount of a disclosed compound disclosed; administeringivacaftor; and administering a CFTR corrector selected from VX-661 andlumacaftor. In a further aspect, this disclosure provides methods oftreating a patient with A455E/F508del CFTR mutation, comprising:administering to the patient an effective amount of a disclosedcompound; administering ivacaftor; and administering a CFTR correctorselected from VX-661 and lumacaftor. In another aspect, this disclosureprovides methods of treating a patient with a G551D Class III CFTRmutation, comprising: administering to the patient an effective amountof a disclosed compound; administering ivacaftor; and administering aCFTR corrector selected from VX-661 and lumacaftor. In a further aspect,this disclosure provides methods of treating a patient withG551D/F508del CFTR mutations, comprising: administering to the patientan effective amount of a disclosed compound; administering ivacaftor;and administering a CFTR corrector selected from VX-661 and lumacaftor.Also provided herein is a method of treating a patient with 3849+10 kbC>T/N1303 CFTR mutations, comprising administering to the patient aneffective amount of a disclosed compound; and optionally administeringivacaftor.

In some embodiments, the methods described herein can further includeadministering an additional therapeutic agent or administering at leasttwo additional CFTR therapeutic agents. In some embodiments, the methodsdescribed herein can further include administering an additional CFTRmodulator or administering at least two additional CFTR modulators. Incertain embodiments, at least one CFTR modulator is a CFTR corrector(e.g., VX-809, VX-661, VX-152, VX-440, VX-983, and GLPG2222) orpotentiator (e.g., ivacaftor, genistein and GLPG1837). In certain ofthese embodiments, one of the at least two additional therapeutic agentsis a CFTR corrector (e.g., VX-809, VX-661, VX-152, VX-440, and VX-983)and the other is a CFTR potentiator (e.g., ivacaftor and genistein). Incertain of these embodiments, one of the at least two additionaltherapeutic agents is a CFTR corrector (e.g., GLPG2222) and the other isa CFTR potentiator (e.g., GLPG1837). In other embodiments, the methodsdescribed herein can further include administrating an epithelial sodiumchannel (ENaC) inhibitor (e.g., VX-371).

In a further aspect, a method of identifying a candidate agent thatincreases CFTR activity is provided, which includes: (i) contacting acell that expresses a CFTR protein with the candidate agent and adisclosed compound; (ii) measuring the CFTR activity in the cell in thepresence of the candidate agent and the disclosed compound; and (iii)comparing the CFTR activity to that in the absence of the test agent,wherein an increase in CFTR activity in the presence of the test agentindicates that the agent increases CFTR activity. In certainembodiments, the cell expresses a mutant CFTR protein. In certainembodiments, CFTR activity is measured by measuring chloride channelactivity of the CFTR, and/or other ion transport activity. In certain ofthese embodiments, the method is high-throughput. In certain of theseembodiments, the candidate agent is a CFTR corrector or a CFTRpotentiator.

DETAILED DESCRIPTION

As used herein, the words “a” and “an” are meant to include one or moreunless otherwise specified. For example, the term “an agent” encompassesboth a single agent and a combination of two or more agents.

As discussed above, the present disclosure is directed in part tomethods of treating CFTR that include administering compounds asdescribed herein having the Formula (I) and (II) or a pharmaceuticallyacceptable salt, prodrug or solvate thereof, and in some embodiments,additionally administering another agent as described here.

In some embodiments, a compound for use in the disclosed methods has theformula (I). In other embodiments, a compound has the formula (II) asprovided below.

and pharmaceutically acceptable salts, stereoisomers, and prodrugsthereof, wherein:

-   -   X₁ is CR₃₃ or N;    -   X₃ is selected from the group consisting of O, S, and NR_(hh);    -   pp is 1, 2, or 3;    -   R₁₁ is independently selected for each occurrence from the group        consisting of hydrogen, halogen, and C₁₋₄ alkyl (optionally        substituted by one, two or three halogens);    -   R₃₁ is selected from the group consisting of hydrogen, halogen,        and C₁₋₄ alkyl;    -   R₃₃ is selected from the group consisting of H, halogen, C₁₋₄        alkyl, and —NR′R″ wherein R′ and R″ are each independently        selected for each occurrence from H and C₁₋₄ alkyl or taken        together with the nitrogen to which they are attached form a        heterocyclic ring;    -   L₁ is selected from the group consisting of C₁₋₆ alkylene, C₃₋₆        cycloalkylene, C₃₋₆ cycloalkylene-C₁₋₄ alkylene, C₁₋₃        alkylene-NR_(hh)—S(O)_(w)—, —C₁₋₃ alkylene-S(O)_(w)—NR_(hh)—,        C₃₋₆ cycloalkylene-C₀₋₂ alkylene-S(O)_(w)—NR_(hh), and C₃₋₆        cycloalkylene-C₀₋₂ alkylene NR_(hh)—S(O)_(w)—, wherein L₁ may be        optionally substituted by one, two or three substituents        selected from the group consisting of halogen, hydroxyl, and        C₁₋₃ alkyl (optionally substituted by one, two or three        substituents each selected independently from R_(ff));    -   R₄₄ is selected from the group consisting of H, halogen,        hydroxyl, C₁₋₃ alkoxy, phenyl, —O-phenyl, —NR′-phenyl,        heterocycle, and a 5-6 membered monocyclic or 8-10 membered        bicyclic heteroaryl having one, two or three heteroatoms each        selected from O, N, and S; wherein phenyl, —O-phenyl,        —NR′-phenyl, heterocycle and heteroaryl may be optionally        substituted by one or two substituents each selected        independently from R_(gg);    -   R_(ff) is selected for each occurrence from group consisting of        halogen, hydroxyl, C₁₋₄ alkyl, C₁₋₄ alkyoxy, C₂₋₄ alkenyl, C₃₋₆        cycloalkyl, —NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl, S(O)_(w)—NR′R″,        and —S(O)_(w)—C₁₋₃ alkyl, where w is 0, 1, or 2, wherein C₁₋₄        alkyl, C₁₋₄ alkyoxy, C₂₋₄ alkenyl and C₃₋₆ cycloalkyl may be        optionally substituted by one, two or three substituents each        independently selected from the group consisting of halogen,        hydroxyl, —NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl, S(O)_(w)—NR′R″, and        —S(O)_(w)—C₁₋₃ alkyl;    -   R_(gg) is selected for each occurrence from the group consisting        of halogen, hydroxyl, cyano, —NR′R″, —NR′—S(O)₂—C₁₋₃ alkyl,        —S(O)_(w)—NR′R″, and —S (O)_(w)—C₁₋₃ alkyl, where w is 0, 1, or        2; heterocycle, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, and C₁₋₆ alkenyl,        wherein C₁₋₆ alkyl, C₃₋₆ cycloalkyl, and C₁₋₆ alkenyl are        optionally substituted by one, two, or three substituents each        independently selected from R_(j) ; and heterocycle is        optionally substituted by one, two, or three substituents each        independently selected from R_(ll);    -   R_(jj) is selected for each occurrence from the group consisting        of halogen, hydroxyl, C₁₋₆ alkoxy (optionally substituted by        one, two, or three substituents each independently selected from        R_(kk)); C₃₋₆ cycloalkyl, C₃₋₆ cycloalkoxy, heterocycle, C(O)OH,        —C(O)OC₁₋₆ alkyl, —NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl,        —S(O)_(w)—NR′R″, and —S(O)_(w)—C₁₋₃ alkyl, where w is 0, 1, or        2;    -   R_(kk) is selected for each occurrence from the group consisting        of halogen, hydroxyl, C₁₋₆ alkyl (optionally substituted by one,        two, or three substituents each independently selected from        halogen, hydroxyl, C₃₋₆ cycloalkyl, and heterocycle (optionally        substituted by C₁₋₆ alkyl)), C₃₋₆ cycloalkyl (optionally        substituted by one, two, or three substituents each        independently selected from halogen, hydroxyl, and C₁₋₆ alkyl),        phenyl, heterocycle (optionally substituted by one, two or three        substituents independently selected from halogen, hydroxyl, and        C₁₋₆ alkyl), and heteroaryl;    -   R_(ll) is selected for each occurrence from the group consisting        of halogen, hydroxyl, C₁₋₆ alkyl (optionally substituted by one,        two, or three substituents each independently selected from        halogen, hydroxyl, and C₃₋₆ cycloalkyl) and heterocycle        (optionally substituted by one, two or three substituents        independently selected from halogen, hydroxyl, and C₁₋₆ alkyl);    -   R′ and R″ are each independently selected for each occurrence        from H, C₁₋₄ alkyl, phenyl and heterocycle;    -   w is 0, 1 or 2; and    -   R_(hh) is selected for each occurrence from the group consisting        of H, C₁₋₆ alkyl and C₃₋₆ cycloalkyl. L₁ is C₁₋₃ alkylene, C₃₋₅        cycloalkylene, or C₃₋₆ cycloalkylene-C₁₋₄ alkylene. For example,        R₃₁ may be H or F.

In certain embodiments, R_(gg) is selected from the group consisting of:

wherein R₂₉ is selected from C₁₋₆ alkyl (optionally substituted by one,two or three substituents each independently selected from the groupconsisting of halogen, hydroxyl, C₁₋₆ alkoxy, and cycloalkyl) andheterocycle (optionally substituted by one, two or three substituentseach independently selected from the group consisting of halogen,hydroxyl, C₁₋₆ alkyl and C₁₋₆ alkoxy).

R₂₉, in certain embodiments, may be selected from the group consistingof:

For example, provided herein is a compound:

wherein qq is 0 or 1, for example a compound, represented by:

R₄₄ may be selected, for example, from the group consisting of:pyrrolidinyl, piperidinyl, tetrahydropyranyl, and tetrahydrofuranyl, ormay be selected from the group consisting of:

wherein X independently for each occurrence is selected from the groupconsisting of O, S, NR_(hh), C, C(R₈₈), and C(R₈₈)(R₉₉); X₂independently for each occurrence is selected from the group consistingof O, S and NR_(hh); R″ is H or C₁₋₄alkyl; and each R₆₆, R₇₇, R₈₈ andR₉₉ is independently selected for each occurrence from H and R_(gg), andn is 0, 1, 2, or 3.

Each R₆₆, R₇₇, R₈₈ and R₉₉ may be independently selected for eachoccurrence in certain embodiments, from the group consisting ofhydrogen, halogen, hydroxyl, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, andheterocycle, wherein C₁₋₆ alkyl, C₃₋₆ cycloalkyl, and heterocycle areoptionally substituted by one, two or three substituents eachindependently selected from the group consisting of hydroxyl, C₁₋₆alkyl, C₁₋₆ alkoxy (optionally substituted by C₃₋₆cycloalkyl,heterocycle, —C₁₋₂alkyl-heterocycle and C₁₋₂alkyl-C₃₋₆cycloalkyl),—S(O)_(w)—C₁₋₃ alkyl (w is 0,1, or 2) and NR′S(O)₂C₁₋₆ alkyl; and R′ isindependently selected for each occurrence from H and C₁₋₄ alkyl.

For example, pp is 0, 1 or 2, and R₁₁ is selected from H, F, or methyl.

In certain of these embodiments, L₁ is C₁₋₃ alkylene or C₃₋₅cycloalkylene.

In certain of these embodiments, R₃₁ is H or F.

In certain of these embodiments, a disclosed compound has the formula:

wherein qq is 0 or 1.

For example, the compound can have the following formula:

In certain embodiments, R₄₄ is selected from the group consisting of:pyrrolidinyl, piperidinyl, tetrahydropyranyl, and tetrahydofuranyl.

In other embodiments, R₄₄ is selected from the group consisting of

wherein X₂ independently for each occurrence is selected from the groupconsisting of O, S or NR_(hh); and each R₆₆, R₇₇ and R₈₈ isindependently selected for each occurrence from R_(gg).

In certain of these embodiments, each of R₆₆, R₇₇ and R₈₈ is selectedfrom the group consisting of H, halogen, methyl (optionally substitutedby one, two or three substituents each selected from halogen, hydroxyl,methoxy and ethoxy), ethyl (optionally substituted by one, two or threesubstituents each selected from halogen, hydroxyl, methoxy and ethoxy),propyl ((optionally substituted by one, two or three substituents eachselected from halogen, hydroxyl, methoxy and ethoxy), isopropyl((optionally substituted by one, two or three substituents each selectedfrom halogen, hydroxyl, methoxy and ethoxy), n-butyl (optionallysubstituted by one, two or three substituents each selected fromhalogen, hydroxyl, methoxy and ethoxy), t-butyl (optionally substitutedby one, two or three substituents each selected from halogen, hydroxyl,methoxy and ethoxy), s-butyl (optionally substituted by one, two orthree substituents each selected from halogen, hydroxyl, methoxy andethoxy) and isobutyl (optionally substituted by one, two or threesubstituents each selected from halogen, hydroxyl, methoxy and ethoxy).

In certain embodiments, pp is 0, 1 or 2, and R₁₁ is selected from H, F,or methyl.

Exemplary compounds of Formulae (I) and (II) are shown below in Table 1and throughout this disclosure, including the examples and the claims.

TABLE 1 # Structure 1

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Also contemplated herein are pharmaceutical compositions that include adisclosed compound such as those compounds having Formula (I) and (II)and a pharmaceutically acceptable carrier or excipient. In certainembodiments, the compositions can include at least one additional CFTRmodulator as described anywhere herein or at least two additional CFTRmodulators, each independently as described anywhere herein.

It is to be understood that the specific embodiments described hereincan be taken in combination with other specific embodiments delineatedherein.

The features and other details of the disclosure will now be moreparticularly described. Before further description of the presentdisclosure, certain terms employed in the specification, examples andappended claims are collected here. These definitions should be read inlight of the remainder of the disclosure and as understood by a personof skill in the art. Unless defined otherwise, all technical andscientific terms used herein have the same meaning as commonlyunderstood by a person of ordinary skill in the art.

It will be appreciated that the description of the present disclosureherein should be construed in congruity with the laws and principals ofchemical bonding.

The term “alkyl”, as used herein, unless otherwise indicated, refers toboth branched and straight-chain saturated aliphatic hydrocarbon groupshaving the specified number of carbon atoms; for example, “C₁-C₁₀ alkyl”denotes alkyl having 1 to 10 carbon atoms, and straight or branchedhydrocarbons of 1-6, 1-4, or 1-3 carbon atoms, referred to herein asC₁₋₆ alkyl, C₁₋₄ alkyl, and C₁₋₃ alkyl, respectively. Examples of alkylinclude, but are not limited to, methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, n-hexyl, 2-methylbutyl,2-methylpentyl, 2-ethylbutyl, 3-methylpentyl, and 4-methylpentyl.

The term, “alkenyl”, as used herein, refers to both straight andbranched-chain moieties having the specified number of carbon atoms andhaving at least one carbon-carbon double bond. Exemplary alkenyl groupsinclude, but are not limited to, a straight or branched group of 2-6 or3-4 carbon atoms, referred to herein as C₂₋₆ alkenyl, and C₃₋₄ alkenyl,respectively. Exemplary alkenyl groups include, but are not limited to,vinyl, allyl, butenyl, pentenyl, etc.

The term, “alkynyl”, as used herein, refers to both straight andbranched-chain moieties having the specified number or carbon atoms andhaving at least one carbon-carbon triple bond.

The term “cycloalkyl,” as used herein, refers to saturated cyclic alkylmoieties having 3 or more carbon atoms, for example, 3-10, 3-6, or 4-6carbons, referred to herein as C₃₋₁₀ cycloalkyl, C₃₋₆ cycloalkyl or C₄₋₆cycloalkyl, respectively for example, examples of cycloalkyl include,but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl and adamantyl.

The term “cycloalkenyl,” as used herein, refers to cyclic alkenylmoieties having 3 or more carbon atoms.

The term “cycloalkynyl,” as used herein, refers to cyclic alkynylmoieties having 5 or more carbon atoms.

“Alkylene” means a straight or branched, saturated aliphatic divalentradical having the number of carbons indicated. “Cycloalkylene” refersto a divalent radical of carbocyclic saturated hydrocarbon group havingthe number of carbons indicated.

The term “alkoxy” as used herein refers to a straight or branched alkylgroup attached to oxygen (alkyl-O—). Exemplary alkoxy groups include,but are not limited to, alkoxy groups of 1-6 or 2-6 carbon atoms,referred to herein as C₁₋₆ alkoxy, and C₂₋₆ alkoxy, respectively.Exemplary alkoxy groups include, but are not limited to methoxy, ethoxy,isopropoxy, etc.

The term “heterocyclic” or “heterocycle” encompasses heterocycloalkyl,heterocycloalkenyl, heterobicycloalkyl, heterobicycloalkenyl,heteropolycycloalkyl, heteropolycycloalkenyl, and the like unlessindicated otherwise. Heterocycloalkyl refers to cycloalkyl groupscontaining one or more heteroatoms (O, S, or N) within the ring.Heterocycloalkenyl as used herein refers to cycloalkenyl groupscontaining one or more heteroatoms (O, S or N) within the ring.Heterobicycloalkyl refers to bicycloalkyl groups containing one or moreheteroatoms (O, S or N) within a ring. Heterobicycloalkenyl as usedherein refers to bicycloalkenyl groups containing one or moreheteroatoms (O, S or N) within a ring. A heterocycle can refer to, forexample, a saturated or partially unsaturated 4- to 12 or 4-10-memberedring structure, including bridged or fused rings, and whose ringstructures include one to three heteroatoms, such as nitrogen, oxygen,and sulfur. Where possible, heterocyclic rings may be linked to theadjacent radical through carbon or nitrogen. Examples of heterocyclicgroups include, but are not limited to, pyrrolidine, piperidine,morpholine, thiomorpholine, piperazine, oxetane, azetidine,tetrahydrofuran or dihydrofuran etc.

Cycloalkyl, cycloalkenyl, heterocyclic, groups also include groupssimilar to those described above for each of these respectivecategories, but which are substituted with one or more oxo moieties.

The term “aryl”, as used herein, refers to mono- or polycyclic aromaticcarbocyclic ring systems. A polycyclic aryl is a polycyclic ring systemthat comprises at least one aromatic ring. Polycyclic aryls can comprisefused rings, covalently attached rings or a combination thereof. Theterm “aryl” embraces aromatic radicals, such as, phenyl, naphthyl,indenyl, tetrahydronaphthyl, and indanyl. An aryl group may besubstituted or unsubstituted. In some embodiments, the aryl is a C₄-C₁₀aryl. Examples of optionally substituted aryl are phenyl, substitutedphenyl, napthyl and substituted naphthyl.

The term “heteroaryl”, as used herein, refers to aromatic carbocyclicgroups containing one or more heteroatoms (O, S, or N) within a ring. Aheteroaryl group, unless indicated otherwise, can be monocyclic orpolycyclic. A heteroaryl group may additionally be substituted orunsubstituted. The heteroaryl groups of this disclosure can also includering systems substituted with one or more oxo moieties. A polycyclicheteroaryl can comprise fused rings, covalently attached rings or acombination thereof. A polycyclic heteroaryl is a polycyclic ring systemthat comprises at least one aromatic ring containing one or moreheteroatoms within a ring. Examples of heteroaryl groups include, butare not limited to, pyridinyl, pyridazinyl, imidazolyl, pyrimidinyl,pyrazolyl, triazolyl, pyrazinyl, quinolyl, isoquinolyl, tetrazolyl,furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl,quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzofuranyl,cinnolinyl, indazolyl, indolizinyl, phthalazinyl, triazinyl, isoindolyl,purinyl, oxadiazolyl, thiadiazolyl, furazanyl, benzofurazanyl,benzothiophenyl, benzotriazolyl, benzothiazolyl, benzoxazolyl,quinazolinyl, quinoxalinyl, naphthyridinyl, dihydroquinolyl,tetrahydroquinolyl, dihydroisoquinolyl, tetrahydroisoquinolyl,benzofuryl, furopyridinyl, pyrolopyrimidinyl, thiazolopyridinyl,oxazolopyridinyl and azaindolyl. The foregoing heteroaryl groups may beC-attached or heteroatom-attached (where such is possible). Forinstance, a group derived from pyrrole may be pyrrol-1-yl (N-attached)or pyrrol-3-yl (C-attached). In some embodiments, the heteroaryl is 4-to 12-membered heteroaryl. In yet other embodiments, the heteroaryl is amono or bicyclic 4- to 10-membered heteroaryl.

The term “substituted” refers to substitution by independent replacementof one, two, or three or more of the hydrogen atoms with substituentsincluding, but not limited to, and unless indicated otherwise, —C₁-C₁₂alkyl, —C₂-C₁₂ alkenyl, —C₂-C₁₂ alkynyl, —C₃-C₁₂ cycloalkyl, —C₃-C₁₂cycloalkenyl, C₃-C₁₂ cycloalkynyl, -heterocyclic, —F, —Cl, —Br, —I, —OH,—NO₂, —N₃, —CN, —NH₂, oxo, thioxo, —NHR_(x), —NR_(x)R_(x), dialkylamino,-diarylamino, -diheteroarylamino, —OR_(x), —C(O)R_(y), —C(O)C(O)R_(y),—OCO₂R_(y), —OC(O)R_(y), OC(O)C(O)R_(y), —NHC(O)R_(y), —NHCO₂R_(y),—NHC(O)C(O)R_(y), NHC(S)NH₂, —NHC(S)NHR_(x), —NHC(NH)NH₂,—NHC(NH)NHR_(x), —NHC(NH)R_(x), —C(NH)NHR_(x), and (C═NR_(x))R_(x);—NRxC(O)R_(x), —NR_(x)C(O)N(R_(x))₂, —NRxCO₂R_(y), —NRxC(O)C(O)R_(y),—NR_(x)C(S)NH₂, —NR_(x)C(S)NHR_(x), —NR_(x)C(NH)NH₂,—NR_(x)C(NH)NHR_(x), —NR_(x)C(NH)R_(x), —C(NRx)NHR_(x) —S(O)R_(y),—NHSO₂R_(x), —CH₂NH₂, —CH₂SO₂CH₃, -aryl, -arylalkyl, -heteroaryl,-heteroarylalkyl, -heterocycloalkyl, —C₃-C₁₂ cycloalkyl,-polyalkoxyalkyl, -polyalkoxy, -methoxymethoxy, -methoxyethoxy, —SH,—S—R_(x), or -methylthiomethyl, wherein R_(x) is selected from the groupconsisting of hydrogen, —C₁-C₁₂ alkyl, —C₂-C₁₂ alkenyl, —C₂-C₁₂ alkynyl,—C₃-C₁₂ cycloalkyl, -aryl, -heteroaryl and -heterocyclic and —R_(y) isselected from the group consisting of hydrogen, —C₁-C₁₂ alkyl, —C₂-C₁₂alkenyl, —C₂-C₁₂ alkynyl, —C₃-C₁₂ cycloalkyl, -aryl, -heteroaryl,-heterocyclic, —NH₂, —NH—C₁-C₁₂ alkyl, —NH—C₂-C₁₂ alkenyl,—NH—C₂-C₁₂-alkynyl, —NH—C₃-C₁₂ cycloalkyl, —NH-aryl, —NH-heteroaryl and—NH-heterocyclic. It is understood that the aryls, heteroaryls, alkyls,and the like can be further substituted.

The terms “halo” or “halogen” as used herein refer to F, Cl, Br, or I.

The term “haloalkyl” as used herein refers to an alkyl group having 1 to(2n+1) substituent(s) independently selected from F, Cl, Br or I, wheren is the maximum number of carbon atoms in the alkyl group. It will beunderstood that haloalkyl is a specific example of an optionallysubstituted alkyl.

The terms “hydroxy” and “hydroxyl” as used herein refers to the radical—OH.

As will be understood by the skilled artisan, “H” is the symbol forhydrogen, “N” is the symbol for nitrogen, “S” is the symbol for sulfur,“O” is the symbol for oxygen. “Me” is an abbreviation for methyl.

The compounds of the disclosure may contain one or more chiral centersand, therefore, exist as stereoisomers. The term “stereoisomers” whenused herein consist of all enantiomers or diastereomers. These compoundsmay be designated by the symbols “(+),” “(−),” “R” or “S,” depending onthe configuration of substituents around the stereogenic carbon atom,but the skilled artisan will recognize that a structure may denote achiral center implicitly. The present disclosure encompasses variousstereoisomers of these compounds and mixtures thereof. Mixtures ofenantiomers or diastereomers may be designated “(±)” in nomenclature,but the skilled artisan will recognize that a structure may denote achiral center implicitly.

The compounds of the disclosure may contain one or more double bondsand, therefore, exist as geometric isomers resulting from thearrangement of substituents around a carbon-carbon double bond. Thesymbol

denotes a bond that may be a single, double or triple bond as describedherein. Substituents around a carbon-carbon double bond are designatedas being in the “Z” or “F” configuration wherein the terms “Z” and “F”are used in accordance with IUPAC standards. Unless otherwise specified,structures depicting double bonds encompass both the “E” and “Z”isomers. Substituents around a carbon-carbon double bond alternativelycan be referred to as “cis” or “trans,” where “cis” representssubstituents on the same side of the double bond and “trans” representssubstituents on opposite sides of the double bond.

Compounds of the disclosure may contain a carbocyclic or heterocyclicring and therefore, exist as geometric isomers resulting from thearrangement of substituents around the ring. The arrangement ofsubstituents around a carbocyclic or heterocyclic ring are designated asbeing in the “Z” or “E” configuration wherein the terms “Z” and “E” areused in accordance with IUPAC standards. Unless otherwise specified,structures depicting carbocyclic or heterocyclic rings encompass both“Z” and “E” isomers. Substituents around a carbocyclic or heterocyclicring may also be referred to as “cis” or “trans”, where the term “cis”represents substituents on the same side of the plane of the ring andthe term “trans” represents substituents on opposite sides of the planeof the ring. Mixtures of compounds wherein the substituents are disposedon both the same and opposite sides of plane of the ring are designated“cis/trans.”

Individual enantiomers and diasterisomers of compounds of the presentdisclosure can be prepared synthetically from commercially availablestarting materials that contain asymmetric or stereogenic centers, or bypreparation of racemic mixtures followed by resolution methods wellknown to those of ordinary skill in the art. These methods of resolutionare exemplified by (1) attachment of a mixture of enantiomers to achiral auxiliary, separation of the resulting mixture of diastereomersby recrystallization or chromatography and liberation of the opticallypure product from the auxiliary, (2) salt formation employing anoptically active resolving agent, (3) direct separation of the mixtureof optical enantiomers on chiral liquid chromatographic columns or (4)kinetic resolution using stereoselective chemical or enzymatic reagents.Racemic mixtures can also be resolved into their component enantiomersby well known methods, such as chiral-phase liquid chromatography orcrystallizing the compound in a chiral solvent. Stereoselectivesyntheses, a chemical or enzymatic reaction in which a single reactantforms an unequal mixture of stereoisomers during the creation of a newstereocenter or during the transformation of a pre-existing one, arewell known in the art. Stereoselective syntheses encompass both enantio-and diastereoselective transformations, and may involve the use ofchiral auxiliaries. For examples, see Carreira and Kvaerno, Classics inStereoselective Synthesis, Wiley-V C H: Weinheim, 2009. Where aparticular compound is described or depicted, it is intended toencompass that chemical structure as well as tautomers of thatstructure.

The term “enantiomerically pure” means a stereomerically purecomposition of a compound. For example, a stereochemically purecomposition is a composition that is free or substantially free of otherstereoisomers of that compound. In another example, for a compoundhaving one chiral center, an enantiomerically pure composition of thecompound is free or substantially free of the other enantiomer. In yetanother example, for a compound having two chiral centers, anenantiomerically pure composition is free or substantially free of theother diastereomers.

Where a particular stereochemistry is described or depicted it isintended to mean that a particular enantiomer is present in excessrelative to the other enantiomer. A compound has an R-configuration at aspecific position when it is present in excess compared to the compoundhaving an S-configuration at that position. A compound has anS-configuration at a specific position when it is present in excesscompared to the compound having an R-configuration at that position.

The compounds disclosed herein can exist in solvated as well asunsolvated forms with pharmaceutically acceptable solvents such aswater, ethanol, and the like, and it is intended that the disclosureembrace both solvated and unsolvated forms. In one embodiment, thecompound is amorphous. In one embodiment, the compound is a singlepolymorph. In another embodiment, the compound is a mixture ofpolymorphs. In another embodiment, the compound is in a crystallineform.

The disclosure also embraces isotopically labeled compounds of thedisclosure which are identical to those recited herein, except that oneor more atoms are replaced by an atom having an atomic mass or massnumber different from the atomic mass or mass number usually found innature. Examples of isotopes that can be incorporated into compounds ofthe disclosure include isotopes of hydrogen, carbon, nitrogen, oxygen,phosphorus, sulfur, fluorine and chlorine, such as ²H, ³H, ¹³C, ¹⁴C,¹⁵N, ¹⁸O, ¹⁷O, ³¹P, ³²S, ³⁵S, ¹⁸F, an₃₆ Cl, respectively. For example, acompound of the disclosure may have one or more H atom replaced withdeuterium.

Certain isotopically-labeled disclosed compounds (e.g., those labeledwith ³H and ¹⁴C) are useful in compound and/or substrate tissuedistribution assays. Tritiated (i.e., ³H) and carbon-14 (i.e., ¹⁴C)isotopes are particularly suitable for their ease of preparation anddetectability. Further, substitution with heavier isotopes such asdeuterium (i.e., ²H) may afford certain therapeutic advantages resultingfrom greater metabolic stability (e.g., increased in vivo half-life orreduced dosage requirements) and hence may be suitable in somecircumstances. Isotopically labeled compounds of the disclosure cangenerally be prepared by following procedures analogous to thosedisclosed in the examples herein by substituting an isotopically labeledreagent for a non-isotopically labeled reagent.

The disclosure additionally encompasses embodiments wherein one or moreof the nitrogen atoms in a disclosed compound are oxidized to N-oxide.

Representative and exemplary synthetic routes for the preparation ofcompounds described herein are shown in the schemes below and throughoutthe Examples section. As will be understood by the skilled artisan,diastereomers can be separated from the reaction mixture using columnchromatography.

Compounds of the disclosure can also be prepared using methods describedin the literature, including, but not limited to, J. Med. Chem. 2011,54(13), 4350-64; Russian Journal of Organic Chemistry 2011, 47(8),1199-1203; U.S. Patent Application Publication No. 2009/0036451 A1;WO2008/046072 A2, and U.S. Pat. No. 4,336,264, the contents of each ofwhich are expressly incorporated by reference herein.

As discussed above, the disclosure encompasses to a method of enhancing(e.g., increasing) CFTR activity in a subject (e.g., a subject sufferingfrom any one or more of the conditions described herein) comprisingadministering a compound of the disclosure in an effective amount. Thedisclosure also encompasses a method of treating a patient sufferingfrom a condition associated with CFTR activity comprising administeringto said patient an effective amount of a compound described herein. Incertain embodiments, the disease is cystic fibrosis.

“Treating” or “treatment” includes preventing or delaying the onset ofthe symptoms, complications, or biochemical indicia of a disease,alleviating or ameliorating the symptoms or arresting or inhibitingfurther development of the disease, condition, or disorder. A “subject”is an animal to be treated or in need of treatment. A “patient” is ahuman subject in need of treatment.

An “effective amount” refers to that amount of an agent that issufficient to achieve a desired and/or recited effect. In the context ofa method of treatment, an “effective amount” of the therapeutic agentthat is sufficient to ameliorate of one or more symptoms of a disorderand/or prevent advancement of a disorder, cause regression of thedisorder and/or to achieve a desired effect.

The term “modulating” encompasses increasing, enhancing, inhibiting,decreasing, suppressing, and the like. The terms “increasing” and“enhancing” mean to cause a net gain by either direct or indirect means.As used herein, the terms “inhibiting” and “decreasing” encompasscausing a net decrease by either direct or indirect means.

In some examples, CFTR activity is enhanced after administration of acompound described herein when there is an increase in the CFTR activityas compared to that in the absence of the administration of thecompound. CFTR activity encompasses, for example, chloride channelactivity of the CFTR, and/or other ion transport activity (for example,HCO₃ ⁻ transport). In certain of these embodiments, the activity of oneor more (e.g., one or two) mutant CFTRs (e.g., ΔF508, S549N, G542X,G551D, R117H, N1303K, W1282X, R553X, 621+1G>T, 1717−1G>A, 3849+10 kbC>T,2789+5G>A, 3120+1G>A, I507del, R1162X, 1898+1G>A, 3659delC, G85E,D1152H, R560T, R347P, 2184insA, A455E, R334W, Q493X, and 2184delA CFTR)is enhanced (e.g., increased). Contemplated patients may have a CFTRmutation(s) from one or more classes, such as without limitation, ClassI CFTR mutations, Class II CFTR mutations, Class III CFTR mutations,Class IV CFTR mutations, Class V CFTR mutations, and Class VI mutations.Contemplated subject (e.g., human subject) CFTR genotypes include,without limitation, homozygote mutations (e.g., ΔF508/ΔF508 andR117H/R117H) and compound heterozygote mutations (e.g., ΔF508/G551D;ΔF508/A455E; ΔF508/G542X; Δ508F/W1204X; Δ508F/S549N; R553X/W1316X;W1282X/N1303K, 591Δ18/E831X; F508del/R117H/N1303K/3849+10 kbC>T;Δ303K/384 and DF508/G178R).

In certain embodiments, the mutation is a Class I mutation, e.g., aG542X; a Class II/I mutation, e.g., a ΔF508/G542X compound heterozygousmutation. In other embodiments, the mutation is a Class III mutation,e.g., a G551D; a Class II/Class III mutation, e.g., a ΔF508/G551Dcompound heterozygous mutation. In still other embodiments, the mutationis a Class V mutation, e.g., a A455E; Class II/Class V mutation, e.g., aΔF508/A455E compound heterozygous mutation. Of the more than 1000 knownmutations of the CFTR gene, ΔF508 is the most prevalent mutation of CFTRwhich results in misfolding of the protein and impaired trafficking fromthe endoplasmic reticulum to the apical membrane (Dormer et al. (2001),J. Cell Sci. 114, 4073-4081; http://www.genet.sickkids.on.ca/app). Incertain embodiments, ΔF508 CFTR activity is enhanced (e.g., increased).In certain embodiments, ΔF508 CFTR activity and/or G542X CFTR activityand/or G551D CFTR activity and/or A455E CFTR activity is enhanced (e.g.,increased). An enhancement of CFTR activity can be measured, forexample, using literature described methods, including for example,Ussing chamber assays, patch clamp assays, and hBE Ieq assay (Devor etal. (2000), Am. J. Physiol. Cell Physiol. 279(2): C461-79; Dousmanis etal. (2002), J. Gen. Physiol. 119(6): 545-59; Bruscia et al. (2005), PNAS103(8): 2965-2971).

As discussed above, the disclosure also encompasses a method of treatingcystic fibrosis. The present disclosure can also be used to treat otherconditions associated with CFTR activity, including conditionsassociated with deficient CFTR activity.

In some embodiments, the disclosure is directed to a method of treatinga condition associated with deficient or decreased CFTR activitycomprising administering an effective amount of a compound of Formula(Ia) or (Ib) that enhances CFTR activity. Non-limiting examples ofconditions associated with deficient CFTR activity are cystic fibrosis,congenital bilateral absence of vas deferens (CBAVD), acute, recurrent,or chronic pancreatitis, disseminated bronchiectasis, asthma, allergicpulmonary aspergillosis, smoking-related lung diseases, such as chronicobstructive pulmonary disease (COPD), chronic sinusitis, dry eyedisease, protein C deficiency, Aβ-lipoproteinemia, lysosomal storagedisease, type 1 chylomicronemia, mild pulmonary disease, lipidprocessing deficiencies, type 1 hereditary angioedema,coagulation-fibrinolyis, hereditary hemochromatosis, CFTR-relatedmetabolic syndrome, chronic bronchitis, constipation, pancreaticinsufficiency, hereditary emphysema, and Sjogren's syndrome.

In some embodiments, disclosed methods of treatment further compriseadministering an additional therapeutic agent. For example, in anembodiment, provided herein is a method of administering a disclosedcompound and at least one additional therapeutic agent. In certainaspects, a disclosed method of treatment comprises administering adisclosed compound, and at least two additional therapeutic agents.Additional therapeutic agents include, for example, mucolytic agents,bronchodilators, antibiotics, anti-infective agents, anti-inflammatoryagents, ion channel modulating agents, therapeutic agents used in genetherapy, CFTR correctors, and CFTR potentiators, or other agents thatmodulates CFTR activity. In some embodiments, at least one additionaltherapeutic agent is selected from the group consisting of a CFTRcorrector and a CFTR potentiator. Non-limiting examples of CFTRcorrectors and potentiators include VX-770 (Ivacaftor), deuteratedIvacaftor, GLPG2851, GLPG2737, GLPG2451, VX-809(3-(6-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)cyclopropanecarboxamido)-3-methylpyridin-2-yl)benzoicacid, VX-661(1-(2,2-difluoro-1,3-benzodioxol-5-yl)-N-[1-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(2-hydroxy-1,1-dimethylethyl)-1H-indol-5-yl]-cyclopropanecarboxamide),VX-983, VX-152, VX-440, and Ataluren (PTC124)(3-[5-(2-fluorophenyl)-1,2,4-oxadiazol-3-yl]benzoic acid), FDL169,GLPG1837/ABBV-974 (for example, a CFTR potentiator), GLPG2665, GLPG2222(for example, a CFTR corrector); and compounds described in, e.g.,WO2014/144860 and 2014/176553, hereby incorporated by reference.Non-limiting examples of modulators include QBW-251, QR-010, NB-124,riociquat, and compounds described in, e.g., WO2014/045283;WO2014/081821, WO2014/081820, WO2014/152213; WO2014/160440,WO2014/160478, US2014027933; WO2014/0228376, WO2013/038390,WO2011/113894, WO2013/038386; and WO2014/180562, of which the disclosedmodulators in those publications are contemplated as an additionaltherapeutic agent and incorporated by reference. Non-limiting examplesof anti-inflammatory agents include N6022 (3-(5-(4-(1H-imidazol-1-yl)phenyl)-1-(4-carbamoyl-2-methylphenyl)-1H-pyrrol-2-yl) propanoic acid),CTX-4430, N1861, N1785, and N91115.

In some embodiments, the methods described herein can further includeadministering an additional therapeutic agent or administering at leasttwo additional CFTR therapeutic agents. In some embodiments, the methodsdescribed herein can further include administering an additional CFTRmodulator or administering at least two additional CFTR modulators. Incertain embodiments, at least one CFTR modulator is a CFTR corrector(e.g., VX-809, VX-661, VX-983, VX-152, VX-440, and GLPG2222 or GLPG2665)or potentiator (e.g., ivacaftor, genistein and GLPG1837). In certain ofthese embodiments, one of the at least two additional therapeutic agentsis a CFTR corrector (e.g., VX-809, VX-661, VX-152, VX-440, and VX-983)and the other is a CFTR potentiator (e.g., ivacaftor and genistein). Incertain of these embodiments, one of the at least two additionaltherapeutic agents is a CFTR corrector (e.g., GLPG2222) and the other isa CFTR potentiator (e.g., GLPG1837). In certain of these embodiments,one of the at least two additional therapeutic agents is a CFTRcorrector (e.g., VX-809 or VX-661) and the other is a CFTR potentiator(e.g., ivacaftor). In certain of these embodiments, at least one CFTRmodulator is an agent that enhances read-through of stop codons (e.g.,NB124 or ataluren). NB124 has the structure:

In other embodiments, the methods described herein can further includeadministrating an epithelial sodium channel (ENaC) inhibitor (e.g.,VX-371).

Accordingly, in another aspect, this disclosure provides a method oftreating a condition associated with deficient or decreased CFTRactivity (e.g., cystic fibrosis), which includes administering to asubject in need thereof (e.g., a human patient in need thereof) aneffective amount of a disclosed compound and at least one or twoadditional CFTR therapeutic agent(s) (e.g., at least one or twoadditional CFTR therapeutic agents, e.g., in which one of the at leastone or two additional therapeutic agents is optionally a CFTR correctoror modulator (e.g., VX-809, VX-661, VX-983, VX-152, VX-440, GLPG2222,NB124, ataluren) and/or the other is a CFTR potentiator (e.g.,ivacaftor, genistein, and GLPG1837); e.g., one of the at least twoadditional therapeutic agents is GLPG2222, and the other is GLPG1837; orone of the at least two additional therapeutic agents is VX-809 orVX-661, and the other is a ivacaftor). In certain embodiments, thesubject's CFTR genotype includes, without limitation, one or more ClassI CFTR mutations, one or more Class II CFTR mutations, one or more ClassIII CFTR mutations, one or more Class IV CFTR mutations, or one or moreClass V CFTR mutations, or one or more Class VI CFTR mutations. Incertain embodiments, the subject's CFTR genotype includes, withoutlimitation, one or more homozygote mutations (e.g., ΔF508/ΔF508 orR117H/R117H) and/or one or more compound heterozygote mutations (e.g.,ΔF508/G551D; ΔF508/A455E; ΔF508/G542X; Δ508F/W1204X; Δ508F/S549N;R553X/W1316X; W1282X/N1303K; F508del/R117H; N1303K/3849+10 kbC>T;ΔF508/R334W; DF508/G178R; and 591Δ18/E831X). In certain embodiments, thesubject's CFTR genotype includes a Class I mutation, e.g., a G542X ClassI mutation, e.g., a ΔF508/G542X compound heterozygous mutation. In otherembodiments, the subject's CFTR genotype includes a Class III mutation,e.g., a G551D Class III mutation, e.g., a ΔF508/G551D compoundheterozygous mutation. In still other embodiments, the subject's CFTRgenotype includes a Class V mutation, e.g., a A455E Class V mutation,e.g., a ΔF508/A455E compound heterozygous mutation. In certainembodiments, ΔF508 CFTR activity and/or G542X CFTR activity and/or G551DCFTR activity and/or A455E activity is enhanced (e.g., increased). Incertain embodiments, the enhancement in activity (e.g., increase inactivity) provided by the combination of the disclosed compound and oneor two additional therapeutic agents is greater than additive whencompared to the enhancement in activity provided by each therapeuticcomponent individually.

Effect on CFTR Class protein Example of mutation I Shortened proteinW1282X Instead of inserting the or no protein amino acid tryptophan (W),the synthesized protein sequence is prematurely stopped (indicated by anX). II Protein fails to ΔF508 A phenylalanine amino acid reach cell (F)is deleted membrane III Channel cannot G551D A “missense” mutation: beregulated instead of a glycine amino acid (G), properly aspartate (D) isadded IV Reduced chloride R117H Missense conductance V Reduced levels3120 + 1G > A Splice-site mutation in of protein, for gene intron 16example, but not limited to, due to incorrect splicing of gene VIReduced due to N287Y a A −>T at 991 protein instability GenotypeDescription Possible Symptoms Δ508F/Δ508F homozygote Severe lungdisease, pancreatic insufficient R117H/R117H homozygote Congenitalbilateral absence of the vas deferens, No lung or pancreas disease,WT/Δ508F heterozygote Unaffected WT/3120 + 1 G > A heterozygoteUnaffected Δ508F/W1204X compound No lung disease, pancreaticheterozygote insufficient R553X and W1316X compound Mild lung disease,heterozygote pancreatic insufficient 591Δ18/E831X compound No lung orpancreas disease, heterozygote nasal polyps

For example, provided herein is a method of treating a patient havingone or more of the following mutations in the CFTR gene: G1244E G1349D,G178R, G551S, S1251N, S1255P, S549N, S549R, G970R, or R117H, and/ore.g., a patient with one or two copies of the F508del mutation, or onecopy of the ΔF508 mutation and a second mutation that results in agating effect in the CFTR protein (e.g., a patient that is heterozygousfor ΔF508 and G551D mutation), a patient with one copy of the ΔF508mutation and a second mutation that results in residual CFTR activity ,or a patient with one copy of the ΔF508 mutation and a second mutationthat results in residual CFTR activity, comprising administering aneffective amount of a disclosed compound. As described herein, suchexemplary methods (e.g., of a patient having one or mutations such asthose described above) may include, for example, administering to suchpatient a combination therapy, e.g., administering (simultaneously orsequentially) an effective amount of ivacaftor to said patient and aneffective amount of disclosed compound that may act as an amplifier.Such administration may result, for example, in increased chloridetransport in human bronchial epithelial cells with e.g., one or twocopies of mutations, e.g, ΔF508 mutation, as compared to administrationof ivacaftor alone. Another combination therapy that includes adisclosed compound may also include an effective amount of a readthroughagent (e.g., ataluren, NB124) and an effect amount of disclosed compoundthat may act as an amplifier. Without being limited by theory, theincrease in immature CFTR protein levels elicited by amplifiers such asthose disclosed herein can result in CFTR mRNA stabilization, which isconsistent with a model that disclosed compounds work by enhancing CFTRefficiency. For example, acting at an early step in CFTR synthesis toprovide more protein, amplifier (e.g., as disclosed herein) can beuseful in combinations to boost the activity of additional CFTRmodulators.

The phrase “combination therapy,” as used herein, refers to anembodiment where a patient is co-administered a disclosed compound, aCFTR potentiator agent (e.g., ivacaftor) and optionally, one or moreCFTR corrector agent(s) (e.g, VX-661 and/or lumacaftor) as part of aspecific treatment regimen intended to provide the beneficial effectfrom the co-action of these therapeutic agents. For example, abeneficial effect of a combination may include, but is not limited to,pharmacokinetic or pharmacodynamic co-action resulting from thecombination of therapeutic agents. For example, administration of adisclosed compound with ivacaftor alone or with a CFTR corrector agent(e.g., lumacaftor or VX-661) may result in a level of function (e.g., asmeasured by chloride activity in HBE cells or patients that have a ΔF508mutation, that achieves clinical improvement (or better) as compared tothe chloride activity level in cells or patients with a G551D mutationreceiving ivacaftor alone, or ivacaftor and a corrector agent(lumacaftor or VX-661; or for example, administration of a disclosedcompound with ivacaftor alone or ivacaftor with a CFTR corrector agent(e.g., lumacaftor or VX-661) may result in a level of function (e.g., asmeasured by chloride activity in HBE cells or patients that have a A455Emutation, that achieves clinical improvement (or better) as compared tothe chloride activity level at e.g., 50% or more of wild type cells; orupon administration of a disclosed compound and ivacaftor to a patient(e.g. having a G551D class III mutation) may show e.g., about two timesor more improved activity of ivacaftor as compared to administration ofivacaftor alone. Administration of disclosed therapeutic agents incombination typically is carried out over a defined time period (usuallya day, days, weeks, months or years depending upon the combinationselected). Combination therapy is intended to embrace administration ofmultiple therapeutic agents in a sequential manner, that is, whereineach therapeutic agent is administered at a different time, as well asadministration of these therapeutic agents, or at least two of thetherapeutic agents, in a substantially simultaneous manner Substantiallysimultaneous administration can be accomplished, for example, byadministering to the subject a single tablet or capsule having a fixedratio of each therapeutic agent or in multiple, single capsules for eachof the therapeutic agents. Sequential or substantially simultaneousadministration of each therapeutic agent can be effected by anyappropriate route including, but not limited to, oral routes,inhalational routes, intravenous routes, intramuscular routes, anddirect absorption through mucous membrane tissues. The therapeuticagents can be administered by the same route or by different routes. Forexample, a first therapeutic agent of the combination selected may beadministered by intravenous injection or inhalation or nebulizer whilethe other therapeutic agents of the combination may be administeredorally. Alternatively, for example, all therapeutic agents may beadministered orally or all therapeutic agents may be administered byintravenous injection, inhalation or nebulization.

Combination therapy also can embrace the administration of thetherapeutic agents as described above in further combination with otherbiologically active ingredients and non-drug therapies. Where thecombination therapy further comprises a non-drug treatment, the non-drugtreatment may be conducted at any suitable time so long as a beneficialeffect from the co-action of the combination of the therapeutic agentsand non-drug treatment is achieved. For example, in appropriate cases,the beneficial effect is still achieved when the non-drug treatment istemporally removed from the administration of the therapeutic agents,perhaps by a day, days or even weeks.

The components of a disclosed combination may be administered to apatient simultaneously or sequentially. It will be appreciated that thecomponents may be present in the same pharmaceutically acceptablecarrier and, therefore, are administered simultaneously. Alternatively,the active ingredients may be present in separate pharmaceuticalcarriers, such as, conventional oral dosage forms, that can beadministered either simultaneously or sequentially.

In a further aspect, a method of identifying a candidate agent thatincreases CFTR activity is provided, which includes: (i) contacting acell that expresses a CFTR protein with the candidate agent and adisclosed compound; (ii) measuring the CFTR activity in the cell in thepresence of the candidate agent and the disclosed compound; and (iii)comparing the CFTR activity to that in the absence of the test agent,wherein an increase in CFTR activity in the presence of the test agentindicates that the agent increases CFTR activity. In certainembodiments, the cell expresses a mutant CFTR protein. In certainembodiments, CFTR activity is measured by measuring chloride channelactivity of the CFTR, and/or other ion transport activity. In certain ofthese embodiments, the method is high-throughput. In certain of theseembodiments, the candidate agent is a CFTR corrector or a CFTRpotentiator.

The term “pharmaceutically acceptable salt(s)” as used herein refers tosalts of acidic or basic groups that may be present in a disclosedcompounds used in disclosed compositions. Compounds included in thepresent compositions that are basic in nature are capable of forming awide variety of salts with various inorganic and organic acids. Theacids that may be used to prepare pharmaceutically acceptable acidaddition salts of such basic compounds are those that form non-toxicacid addition salts, i.e., salts containing pharmacologically acceptableanions, including, but not limited to, malate, oxalate, chloride,bromide, iodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate,isonicotinate, acetate, lactate, salicylate, citrate, tartrate, oleate,tannate, pantothenate, bitartrate, ascorbate, succinate, maleate,gentisinate, fumarate, gluconate, glucaronate, saccharate, formate,benzoate, glutamate, methanesulfonate, ethanesulfonate,benzenesulfonate, p-toluenesulfonate and pamoate (i.e.,1,1′-methylene-bis-(2-hydroxy-3-naphthoate)) salts. Compounds includedin the present compositions that are acidic in nature are capable offorming base salts with various pharmacologically acceptable cations.Examples of such salts include alkali metal or alkaline earth metalsalts, particularly calcium, magnesium, sodium, lithium, zinc,potassium, and iron salts. Compounds included in the presentcompositions that include a basic or acidic moiety may also formpharmaceutically acceptable salts with various amino acids. Thecompounds of the disclosure may contain both acidic and basic groups;for example, one amino and one carboxylic acid group. In such a case,the compound can exist as an acid addition salt, a zwitterion, or a basesalt.

Also included in the present disclosure are methods that includeadministering prodrugs of the compounds described herein, for example,prodrugs of a compound of Formula (IIIa), (III), or (IV), or apharmaceutical composition thereof or method of use of the prodrug.

The term “prodrug” refers to compounds that are transformed in vivo toyield a disclosed compound or a pharmaceutically acceptable salt,hydrate or solvate of the compound. The transformation may occur byvarious mechanisms (such as by esterase, amidase, phosphatase, oxidativeand or reductive metabolism) in various locations (such as in theintestinal lumen or upon transit of the intestine, blood or liver).Prodrugs are well known in the art (for example, see Rautio,Kumpulainen, et al., Nature Reviews Drug Discovery 2008, 7, 255). Forexample, if a compound of the disclosure or a pharmaceuticallyacceptable salt, hydrate or solvate of the compound contains acarboxylic acid functional group, a prodrug can comprise an ester formedby the replacement of the hydrogen atom of the acid group with a groupsuch as (C₁₋₈) alkyl, (C₂₋₁₂) alkylcarbonyloxymethyl,1-(alkylcarbonyloxy)ethyl having from 4 to 9 carbon atoms,1-methyl-1-(alkylcarbonyloxy)-ethyl having from 5 to 10 carbon atoms,alkoxycarbonyloxymethyl having from 3 to 6 carbon atoms,1-(alkoxycarbonyloxy)ethyl having from 4 to 7 carbon atoms,1-methyl-1-(alkoxycarbonyloxy)ethyl having from 5 to 8 carbon atoms,N-(alkoxycarbonyl)aminomethyl having from 3 to 9 carbon atoms,1-(N-(alkoxycarbonyl)amino)ethyl having from 4 to 10 carbon atoms,3-phthalidyl, 4-crotonolactonyl, gamma-butyrolacton-4-yl,di-N,N-(C₁₋₂)alkylamino(C₂₋₃)alkyl (such as β-dimethylaminoethyl),carbamoyl-(C₁₋₂)alkyl, N,N-di(C₁₋₂)alkylcarbamoyl-(C₁₋₂)alkyl andpiperidino-, pyrrolidino- or morpholino(C₂₋₃)alkyl.

Similarly, if a compound of the disclosure contains an alcoholfunctional group, a prodrug can be formed by the replacement of thehydrogen atom of the alcohol group with a group such as(C₁₋₆)alkylcarbonyloxymethyl, 1-((C₁₋₆)alkylcarbonyloxy)ethyl,1-methyl-1-(C₁₋₆)alkylcarbonyloxy)ethyl (C₁₋₆)alkoxycarbonyloxymethyl,N-(C₁₋₆)alkoxycarbonylaminomethyl, succinoyl, (C₁₋₆)alkylcarbonyl,α-amino(C₁₋₄)alkylcarbonyl, arylalkylcarbonyl and α-aminoalkylcarbonyl,or α-aminoalkylcarbonyl-α-aminoalkylcarbonyl, where eachα-aminoalkylcarbonyl group is independently selected from the naturallyoccurring L-amino acids, P(O)(OH)₂, -P(O)(O(C₁₋₆)alkyl)₂or glycosyl (theradical resulting from the removal of a hydroxyl group of the hemiacetalform of a carbohydrate).

If a compound of the disclosure incorporates an amine functional group,a prodrug can be formed, for example, by creation of an amide orcarbamate, an N-alkylcarbonyloxyalkyl derivative, an(oxodioxolenyl)methyl derivative, an N-Mannich base, imine or enamine Inaddition, a secondary amine can be metabolically cleaved to generate abioactive primary amine, or a tertiary amine can metabolically cleavedto generate a bioactive primary or secondary amine. For examples, seeSimplício, et al., Molecules 2008, 13, 519 and references therein.

The disclosure additionally includes use of clathrates of the compoundsdescribed herein, pharmaceutical compositions comprising the clathrates,and methods of use of the clathrates. In some embodiments, thedisclosure is directed to clathrates of a disclosed compound of e.g.,Formula (IIIa), (III), or (IV), or a pharmaceutical composition thereof.

As discussed above, the disclosure includes administration ofpharmaceutical compositions comprising a pharmaceutically acceptablecarrier or excipient and a compound described herein. A disclosedcompound, or a pharmaceutically acceptable salt, solvate, clathrate orprodrug thereof, can be administered in pharmaceutical compositionscomprising a pharmaceutically acceptable carrier or excipient. Theexcipient can be chosen based on the expected route of administration ofthe composition in therapeutic applications. The route of administrationof the composition depends on the condition to be treated. For example,intravenous injection may be suitable for treatment of a systemicdisorder and oral administration may be suitable to treat agastrointestinal disorder. The route of administration and the dosage ofthe composition to be administered can be determined by the skilledartisan without undue experimentation in conjunction with standarddose-response studies. Relevant circumstances to be considered in makingthose determinations include the condition or conditions to be treated,the choice of composition to be administered, the age, weight, andresponse of the individual patient, and the severity of the patient'ssymptoms. A pharmaceutical composition comprising a disclosed compoundor a pharmaceutically acceptable salt, solvate, clathrate or prodrug,can be administered by a variety of routes including, but not limitedto, parenteral, oral, pulmonary, ophthalmic, nasal, rectal, vaginal,aural, topical, buccal, transdermal, intravenous, intramuscular,subcutaneous, intradermal, intraocular, intracerebral, intralymphatic,intraarticular, intrathecal and intraperitoneal. The compositions canalso include, depending on the formulation desired,pharmaceutically-acceptable, non-toxic carriers or diluents, which aredefined as vehicles commonly used to formulate pharmaceuticalcompositions for animal or human administration. The diluent is selectedso as not to affect the biological activity of the pharmacologic agentor composition. Examples of such diluents are distilled water,physiological phosphate-buffered saline, Ringer's solutions, dextrosesolution, and Hank's solution. In addition, the pharmaceuticalcomposition or formulation may also include other carriers, adjuvants,or nontoxic, nontherapeutic, nonimmunogenic stabilizers and the like.Pharmaceutical compositions can also include large, slowly metabolizedmacromolecules such as proteins, polysaccharides such as chitosan,polylactic acids, polyglycolic acids and copolymers (such as latexfunctionalized SEPHAROSE™, agarose, cellulose, and the like), polymericamino acids, amino acid copolymers, and lipid aggregates (such as oildroplets or liposomes).

The compositions can be administered parenterally such as, for example,by intravenous, intramuscular, intrathecal or subcutaneous injection.Parenteral administration can be accomplished by incorporating acomposition into a solution or suspension. Such solutions or suspensionsmay also include sterile diluents such as water for injection, salinesolution, fixed oils, polyethylene glycols, glycerine, propylene glycolor other synthetic solvents. Parenteral formulations may also includeantibacterial agents such as, for example, benzyl alcohol or methylparabens, antioxidants such as, for example, ascorbic acid or sodiumbisulfite and chelating agents such as EDTA. Buffers such as acetates,citrates or phosphates and agents for the adjustment of tonicity such assodium chloride or dextrose may also be added. The parenteralpreparation can be enclosed in ampules, disposable syringes or multipledose vials made of glass or plastic.

Additionally, auxiliary substances, such as wetting or emulsifyingagents, surfactants, pH buffering substances and the like can be presentin compositions. Other components of pharmaceutical compositions arethose of petroleum, animal, vegetable, or synthetic origin, for example,peanut oil, soybean oil, and mineral oil. In general, glycols such aspropylene glycol or polyethylene glycol are suitable liquid carriers,particularly for injectable solutions.

Injectable formulations can be prepared either as liquid solutions orsuspensions; solid forms suitable for solution in, or suspension in,liquid vehicles prior to injection can also be prepared. The preparationalso can also be emulsified or encapsulated in liposomes or microparticles such as polylactide, polyglycolide, or copolymer for enhancedadjuvant effect, as discussed above [Langer, Science 249: 1527, 1990 andHanes, Advanced Drug Delivery Reviews 28: 97-119, 1997]. Thecompositions and pharmacologic agents described herein can beadministered in the form of a depot injection or implant preparationwhich can be formulated in such a manner as to permit a sustained orpulsatile release of the active ingredient.

Additional formulations suitable for other modes of administrationinclude oral, intranasal, and pulmonary formulations, suppositories,transdermal applications and ocular delivery. For suppositories, bindersand carriers include, for example, polyalkylene glycols ortriglycerides; such suppositories can be formed from mixtures containingthe active ingredient in the range of about 0.5% to about 10%, or about1% to about 2%. Oral formulations include excipients, such aspharmaceutical grades of mannitol, lactose, starch, magnesium stearate,sodium saccharine, cellulose, and magnesium carbonate. Topicalapplication can result in transdermal or intradermal delivery.Transdermal delivery can be achieved using a skin patch or usingtransferosomes. [Paul et al., Eur. J. Immunol. 25: 3521-24, 1995; Cevcet al., Biochem. Biophys. Acta 1368: 201-15, 1998].

For the purpose of oral therapeutic administration, the pharmaceuticalcompositions can be incorporated with excipients and used in the form oftablets, troches, capsules, elixirs, suspensions, syrups, wafers,chewing gums and the like. Tablets, pills, capsules, troches and thelike may also contain binders, excipients, disintegrating agent,lubricants, glidants, sweetening agents, and flavoring agents. Someexamples of binders include microcrystalline cellulose, gum tragacanthor gelatin. Examples of excipients include starch or lactose. Someexamples of disintegrating agents include alginic acid, corn starch andthe like. Examples of lubricants include magnesium stearate or potassiumstearate. An example of a glidant is colloidal silicon dioxide. Someexamples of sweetening agents include sucrose, saccharin and the like.Examples of flavoring agents include peppermint, methyl salicylate,orange flavoring and the like. Materials used in preparing these variouscompositions should be pharmaceutically pure and non-toxic in theamounts used. In another embodiment, the composition is administered asa tablet or a capsule.

Various other materials may be present as coatings or to modify thephysical form of the dosage unit. For instance, tablets may be coatedwith shellac, sugar or both. A syrup or elixir may contain, in additionto the active ingredient, sucrose as a sweetening agent, methyl andpropylparabens as preservatives, a dye and a flavoring such as cherry ororange flavor, and the like. For vaginal administration, apharmaceutical composition may be presented as pessaries, tampons,creams, gels, pastes, foams or spray.

The pharmaceutical composition can also be administered by nasaladministration. As used herein, nasally administering or nasaladministration includes administering the composition to the mucusmembranes of the nasal passage or nasal cavity of the patient. As usedherein, pharmaceutical compositions for nasal administration of acomposition include therapeutically effective amounts of the compoundsprepared by well-known methods to be administered, for example, as anasal spray, nasal drop, suspension, gel, ointment, cream or powder.Administration of the composition may also take place using a nasaltampon or nasal sponge.

For topical administration, suitable formulations may includebiocompatible oil, wax, gel, powder, polymer, or other liquid or solidcarriers. Such formulations may be administered by applying directly toaffected tissues, for example, a liquid formulation to treat infectionof conjunctival tissue can be administered dropwise to the subject'seye, or a cream formulation can be administered to the skin.

Rectal administration includes administering the pharmaceuticalcompositions into the rectum or large intestine. This can beaccomplished using suppositories or enemas. Suppository formulations caneasily be made by methods known in the art. For example, suppositoryformulations can be prepared by heating glycerin to about 120° C.,dissolving the pharmaceutical composition in the glycerin, mixing theheated glycerin after which purified water may be added, and pouring thehot mixture into a suppository mold.

Transdermal administration includes percutaneous absorption of thecomposition through the skin. Transdermal formulations include patches,ointments, creams, gels, salves and the like.

In addition to the usual meaning of administering the formulationsdescribed herein to any part, tissue or organ whose primary function isgas exchange with the external environment, for purposes of the presentdisclosure, “pulmonary” will also mean to include a tissue or cavitythat is contingent to the respiratory tract, in particular, the sinuses.For pulmonary administration, an aerosol formulation containing theactive agent, a manual pump spray, nebulizer or pressurized metered-doseinhaler as well as dry powder formulations are contemplated. Suitableformulations of this type can also include other agents, such asantistatic agents, to maintain the disclosed compounds as effectiveaerosols.

A drug delivery device for delivering aerosols comprises a suitableaerosol canister with a metering valve containing a pharmaceuticalaerosol formulation as described and an actuator housing adapted to holdthe canister and allow for drug delivery. The canister in the drugdelivery device has a head space representing greater than about 15% ofthe total volume of the canister. Often, the compound intended forpulmonary administration is dissolved, suspended or emulsified in amixture of a solvent, surfactant and propellant. The mixture ismaintained under pressure in a canister that has been sealed with ametering valve.

The disclosure also encompasses the treatment of a condition associatedwith a dysfunction in proteostasis in a subject comprising administeringto said subject an effective amount of a disclosed compound thatenhances, improves or restores proteostasis of a protein. Proteostasisrefers to protein homeostasis. Dysfunction in protein homeostasis is aresult of protein misfolding, protein aggregation, defective proteintrafficking or protein degradation. For example, the disclosureencompasses administering a compound of Formula (Ia) or (Ib) thatcorrects protein misfolding, reduces protein aggregation, corrects orrestores protein trafficking and/or affects protein degradation for thetreatment of a condition associated with a dysfunction in proteostasis.In some aspects of the disclosure, a compound of Formula (Ia) or (Ib)that corrects protein misfolding and/or corrects or restores proteintrafficking is administered. In cystic fibrosis, the mutated ordefective enzyme is the cystic fibrosis transmembrane conductanceregulator (CFTR). One of the most common mutations of this protein isΔF508 which is a deletion (Δ) of three nucleotides resulting in a lossof the amino acid phenylalanine (F) at the 508th (508) position on theprotein. As described above, mutated cystic fibrosis transmembraneconductance regulator exists in a misfolded state and is characterizedby altered trafficking as compared to the wild type CFTR. Additionalexemplary proteins of which there can be a dysfunction in proteostasis,for example that can exist in a misfolded state, include, but are notlimited to, glucocerebrosidase, hexosamine A, aspartylglucosaminidase,α-galactosidase A, cysteine transporter, acid ceramidase, acidα-L-fucosidase, protective protein, cathepsin A, acid β-glucosidase,acid β-galactosidase, iduronate 2-sulfatase, α-L-iduronidase,galactocerebrosidase, acid α-mannosidase, acid β-mannosidase,arylsulfatase B, arylsulfatase A, N-acetylgalactosamine-6-sulfatesulfatase, acid β-galactosidase,N-acetylglucosamine-1-phosphotransferase, acid sphingmyelinase, NPC-1,acid α-glucosidase, β-hexosamine B, heparin N-sulfatase,α-N-acetylglucosaminidase, α-glucosaminide N-acetyltransferase,N-acetylglucosamine-6-sulfate sulfatase, α-N-acetylgalactosaminidase,α-neuramidase, β-glucuronidase, β-hexosamine A and acid lipase,polyglutamine, α-synuclein, TDP-43, superoxide dismutase (SOD),Aαpeptide, tau protein transthyretin and insulin. The disclosedcompounds may be used to restore proteostasis (e.g., correct foldingand/or alter trafficking) of the proteins described above.

Protein conformational diseases encompass gain of function disorders andloss of function disorders. In one embodiment, the proteinconformational disease is a gain of function disorder. The terms “gainof function disorder,” “gain of function disease,” “gain of toxicfunction disorder” and “gain of toxic function disease” are usedinterchangeably herein. A gain of function disorder is a diseasecharacterized by increased aggregation-associated proteotoxicity. Inthese diseases, aggregation exceeds clearance inside and/or outside ofthe cell. Gain of function diseases include, but are not limited to,neurodegenerative diseases associated with aggregation of polyglutamine,Lewy body diseases, amyotrophic lateral sclerosis,transthyretin-associated aggregation diseases, Alzheimer's disease,Machado-Joseph disease, cerebral B-amyloid angiopathy, retinal ganglioncell degeneration, tautopathies (progressive supranuclear palsy,corticobasal degeneration, frontotemporal lobar degeneration), cerebralhemorrhage with amyloidosis, Alexander disease, Serpinopathies, familialamyloidotic neuropathy, senile systemic amyloidosis, ApoAI amyloidosis,ApoAII amyloidosis, ApoAIV amyloidosis, familial amyloidosis of theFinnish type, lysozyme amyloidosis, fibrinogen amyloidosis, dialysisamyloidosis, inclusion body myositis/myopathy, cataracts, medullarythyroid carcinoma, cardiac atrial amyloidosis, pituitary prolactinoma,hereditary lattice corneal dystrophy, cutaneous lichen amyloidosis,corneal lactoferrin amyloidosis, corneal lactoferrin amyloidosis,pulmonary alveolar proteinosis, odontogenic tumor amyloid, seminalvesical amyloid, sickle cell disease, critical illness myopathy, vonHippel-Lindau disease, spinocerebellar ataxia 1, Angelman syndrome,giant axon neuropathy, inclusion body myopathy with Paget disease ofbone, frontotemporal dementia (IBMPFD) and prion diseases.Neurodegenerative diseases associated with aggregation of polyglutamineinclude, but are not limited to, Huntington's disease, dentatorubral andpallidoluysian atrophy, several forms of spino-cerebellar ataxia, andspinal and bulbar muscular atrophy Alzheimer's disease is characterizedby the formation of two types of aggregates: extracellular aggregates ofAβ peptide and intracellular aggregates of the microtubule associatedprotein tau. Transthyretin-associated aggregation diseases include, forexample, senile systemic amyloidoses and familial amyloidoticneuropathy. Lewy body diseases are characterized by an aggregation ofα-synuclein protein and include, for example, Parkinson's disease, Lewybody dementia (LBD) and multiple system atrophy (SMA). Prion diseases(also known as transmissible spongiform encephalopathies or TSEs) arecharacterized by aggregation of prion proteins. Exemplary human priondiseases are Creutzfeldt-Jakob Disease (CJD), Variant Creutzfeldt-JakobDisease, Gerstmann-Straussler-Scheinker Syndrome, Fatal FamilialInsomnia and Kuru. In another embodiment, the misfolded protein isalpha-1 anti-trypsin.

In a further embodiment, the protein conformation disease is a loss offunction disorder. The terms “loss of function disease” and “loss offunction disorder” are used interchangeably herein. Loss of functiondiseases are a group of diseases characterized by inefficient folding ofa protein resulting in excessive degradation of the protein. Loss offunction diseases include, for example, lysosomal storage diseases.Lysosomal storage diseases are a group of diseases characterized by aspecific lysosomal enzyme deficiency which may occur in a variety oftissues, resulting in the build-up of molecules normally degraded by thedeficient enzyme. The lysosomal enzyme deficiency can be in a lysosomalhydrolase or a protein involved in the lysosomal trafficking. Lysosomalstorage diseases include, but are not limited to,aspartylglucosaminuria, Fabry's disease, Batten disease, Cystinosis,Farber, Fucosidosis, Galactasidosialidosis, Gaucher's disease (includingTypes 1, 2 and 3), Gm1 gangliosidosis, Hunter's disease, Hurler-Scheie'sdisease, Krabbe's disease, α-Mannosidosis, β-Mannosidosis,Maroteaux-Lamy's disease, Metachromatic Leukodystrophy, Morquio Asyndrome, Morquio B syndrome, Mucolipidosis II, Mucolipidosis III,Neimann-Pick Disease (including Types A, B and C), Pompe's disease,Sandhoff disease, Sanfilippo syndrome (including Types A, B, C and D),Schindler disease, Schindler-Kanzaki disease, Sialidosis, Sly syndrome,Tay-Sach's disease and Wolman disease.

In another embodiment, the disease associated with a dysfunction inproteostasis is a cardiovascular disease. Cardiovascular diseasesinclude, but are not limited to, coronary artery disease, myocardialinfarction, stroke, restenosis and arteriosclerosis. Conditionsassociated with a dysfunction of proteostasis also include ischemicconditions, such as, ischemia/reperfusion injury, myocardial ischemia,stable angina, unstable angina, stroke, ischemic heart disease andcerebral ischemia.

In yet another embodiment, the disease associated with a dysfunction inproteostasis is diabetes and/or complications of diabetes, including,but not limited to, diabetic retinopathy, cardiomyopathy, neuropathy,nephropathy, and impaired wound healing.

In a further embodiment, the disease associated with a dysfunction inproteostasis is an ocular disease including, but not limited to,age-related macular degeneration (AMD), diabetic macular edema (DME),diabetic retinopathy, glaucoma, cataracts, retinitis pigmentosa (RP) anddry macular degeneration.

In yet additional embodiments, the method of the disclosure is directedto treating a disease associated with a dysfunction in proteostasis,wherein the disease affects the respiratory system or the pancreas. Incertain additional embodiments, the methods of the disclosure encompasstreating a condition selected from the group consisting ofpolyendocrinopathy/hyperinsulinemia, diabetes mellitus, Charcot-MarieTooth syndrome, Pelizaeus-Merzbacher disease, and Gorham's Syndrome.

Additional conditions associated with a dysfunction of proteostasisinclude hemoglobinopathies, inflammatory diseases, intermediate filamentdiseases, drug-induced lung damage and hearing loss. The disclosure alsoencompasses methods for the treatment of hemoglobinopathies (such assickle cell anemia), an inflammatory disease (such as inflammatory boweldisease, colitis, ankylosing spondylitis), intermediate filamentdiseases (such as non-alcoholic and alcoholic fatty liver disease) anddrug induced lung damage (such as methotrexate-induced lung damage). Thedisclosure additionally encompasses methods for treating hearing loss,such as noise-induced hearing loss, aminoglycoside-induced hearing loss,and cisplatin-induced hearing loss.

Additional conditions include those associated with a defect in proteintrafficking and that can be treated according to methods of thedisclosure include: PGP mutations, hERG trafficking mutations,nephrongenic diabetes insipidus mutations in the arginine-vasopressinreceptor 2, persistent hyperinsulinemic hypoglycemia of infancy (PHH1)mutations in the sulfonylurea receptor 1, and α1AT.

The disclosure is illustrated by the following examples which are notmeant to be limiting in any way.

EXEMPLIFICATION

The compounds described herein can be prepared in a number of ways basedon the teachings contained herein and synthetic procedures known in theart. In the description of the synthetic methods described below, it isto be understood that all proposed reaction conditions, including choiceof solvent, reaction atmosphere, reaction temperature, duration of theexperiment and workup procedures, can be chosen to be the conditionsstandard for that reaction, unless otherwise indicated. It is understoodby one skilled in the art of organic synthesis that the functionalitypresent on various portions of the molecule should be compatible withthe reagents and reactions proposed. Substituents not compatible withthe reaction conditions will be apparent to one skilled in the art, andalternate methods are therefore indicated. The starting materials forthe examples are either commercially available or are readily preparedby standard methods from known materials. At least some of the compoundsidentified as “intermediates” herein are contemplated as compounds ofthe disclosure.

General Procedure (1) for Amide Coupling:

EDC.HCl (1.98 mmol), HOBt.H₂O (1.32 mmol) and amine (1.45 mmol) wereadded to a solution of 3-phenylisoxazole-5-carboxylic acid (1.32 mmol)in THF (10 mL) at room temperature. The reaction mixture was stirred for15 h at room temperature and concentrated to dryness. The crude solidwas extracted with EtOAc (3×10 mL) and washed with water. The combinedorganic layers were dried over Na₂SO₄ and concentrated to dryness. Thecrude compound was purified by Combiflash to give the correspondingamide.

Example 1 N-(2-methoxyethyl)-3-phenylisoxazole-5-carboxamide

Compound 1 was obtained as an off white solid using the generalprocedure 1 (0.120 g, 37.0%); ¹H-NMR (400 MHz, CDCl₃) δ 7.82-7.79 (m,2H), 7.50-7.45 (m, 3H), 7.21 (s, 1H), 6.98-6.97 (br, 1H), 3.68-3.64 (m,2H), 3.57-3.55 (t, 2H), 3.40 (s, 3H); LCMS [M+H]⁺ 247.2, HPLC purity:99.76% at 220 nm and 99.64% at 254 nm.

Example 23-phenyl-N-((tetrahydrofuran-2-yl)methyl)isoxazole-5-carboxamide

Compound 2 was obtained as a white solid using the general procedure 1(0.110 g, 30.6%); ¹H NMR (400 MHz, CDCl₃) δ 7.82-7.80 (m, 2H), 7.49-7.45(m, 3H), 7.25-7.21 (d, J=14.9 Hz, 1H), 6.95 (br, 1H), 4.08-4.06 (m, 1H),3.92-3.89 (m, 1H), 3.81-3.71 (m, 2H), 3.44-3.39 (m, 1H), 2.06-1.99 (m,1H), 1.96-1.91(m, 2H), 1.63-1.58(m, 1H); LCMS [M+H]⁺ 273.2. HPLC purity:99.78% at 220 nm and 99.79% at 254 nm.

Example 3 N-(2-morpholinoethyl)-3-phenylisoxazole-5-carboxamide

Compound 3 was obtained as a white solid using the general procedure 1(0.125 g, 31.5%); ¹H NMR (400 MHz, CDCl₃) δ 7.82-7.80 (m, 2H), 7.49-7.46(m, 3H), 7.21 (s, 2H), 3.75-3.72 (t, 4H), 3.58-3.53 (q, 2H), 2.61-2.58(t, 2H), 2.51-2.50 (m, 4H); LCMS [M+H]⁺ 302.1, HPLC purity: 99.81% at220 nm and 99.87% at 254 nm.

Example 4 N-(3-(1H-imidazol-1-yl)propyl)-3-phenylisoxazole-5-carboxamide

Compound 4 was obtained as a white solid using the general procedure 1(0.127 g, 32.6%); ¹H NMR (400 MHz, CDCl₃) δppm 7.82-7.79 (m, 2H), 7.52(s, 1H), 7.50-7.46 (m, 3H), 7.22 (s, 1H),7.08 (s, 1H), 6.98-6.97 (m,1H), 6.79-6.76 (m, 1H), 4.08-4.04 (t, 2H), 3.52-3.47 (m, 2H), 2.18-2.11(m, 2H); LCMS [M+H]⁺ 297.2. HPLC purity: 98.05% at 220 nm and 97.78% at254 nm.

Example 5N-(trans-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: tert-butyl (3-oxocyclobutyl)carbamate: DPPA (4.0 g, 1.1 eq.) wasadded dropwise to a cold (−5˜5° C.) solution of3-oxocyclobutanecarboxylic acid (1.5 g, 1.0 eq.) and TEA (1.5 g, 1.1eq.) in toluene (30 mL), and the mixture stirred at −5˜0° C. for 16 h.The reaction mixture was washed with NaHCO₃ (2×9 mL), water (1×9 mL) andNaCl aq. (1×4.5 mL) at 0˜10° C. The organic phase was dried over Na₂SO₄,filtered and t-BuOH (7.5 mL) added to the filtrate. The reaction mixturewas heated at 90˜100° C. for 16 h. The mixture was concentrated undervacuum at 60˜70° C. and then suspended in TBME (4.5 mL), filtered andthe solid dried in air to give 1.15 g (purity: 98.5%, yield: 47.2%) ofproduct as a white solid.

Step 2: tert-butyl (cis-3-hydroxycyclobutyl)carbamate: a solution oftert-butyl (3-oxocyclobutyl)carbamate (200 mg, 1.0 eq.) in THF (1 mL)was added dropwise to a cold (below −70° C.) solution of NaBH₄ (20.4 mg,0.5 eq.) in THF (1.8 mL) and water (2 mL), maintaining the temperatureat −80˜−70° C. (ca. for 2 h for completion of addition). The mixture wasstirred at −60˜−50° C. for 3 h, water (2 mL) was added to the reactionmixture and allowed to reach up to 15° C. The reaction mixture is thenextracted with ethyl acetate (2 mL, 2×1 mL) and the combined organiclayers were washed with brine (1 mL). The organic layer was concentratedunder vacuum at 3˜40° C., the solid dissolved in toluene (1 mL, 80˜90°C.) and gradually cooled to 25-30° C. for 2.5 h. The mixture was stirredfor 2 h at 25-30° C., filtered, and the solid dried in air to give theproduct (177 mg with ratio of cis:trans (96.4:3.6), yield: 87.6%) as anoff-white solid.

Step 3: tert-butyl (trans-3-azidocyclobutyl)carbamate: a solution ofPPh₃ (315 mg) and DIAD (243 mg) in THF (3 mL) was stirred for 20 min at0-10° C. A solution of tert-butyl (cis-3-hydroxycyclobutyl)carbamate(150 mg, 1.0 eq.) and DPPA (265 mg, 1.2 eq.) in THF (1 ml) was addeddropwise, the mixture warmed to 25-30° C., and stirred for 2 h. Brine (3mL) was added to the reaction mixture, extracted with ethyl acetate (3mL) and the combined organic layers concentrated under vacuum to give acrude oil. The mixture was purified by SiO₂ column chromatography andeluted with ethyl acetate/petroleum ether (0%˜10%) gradually. Theproduct was suspended in n-heptane (0.3 mL) and stirred for 0.5 h at20˜25° C. The mixture was filtered and the solid dried in air to givethe product in 85% yield and ratio of cis/trans=4:96 checked by ¹H NMR.

Step 4: tert-butyl(trans-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)carbamate:a solution of tert-butyl (trans-3-azidocyclobutyl)carbamate (246 mg, 1.0eq.) and prop-2-yn-1-ol (326 mg, 5.0 eq.) in DMF (1.2 mL) was heated at90˜95° C. for 20 h. The mixture was concentrated under vacuum at 65° C.to give ˜1:1 mixture of 4 and 5 regioisomers (353 mg). The mixture waspurified by SFC to give tert-butyl(trans-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)carbamate(101 mg, P: 99.9% (205 nm), Y: 32%) as a solid.

Step 5: (1-(trans-3-aminocyclobutyl)-1H-1,2,3-triazol-5-yl)methanolhydrochloride: tert-butyl(trans-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)carbamate(101 mg, 1.0 eq.) was added slowly (5 portions) to a solution ofHCl/dioxane (3.5 mol/L, 2 mL) at 20˜30° C. and stirred for 18 h at20˜30° C. The reaction mixture was concentrated under vacuum at 55° C.to give the product (93.4 mg, assay 67% based on free base, Y: 100%) asa solid.

Step 6:N-(trans-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:DIPEA (388 mg, 3.00 mmol, 3.00 equiv) was added dropwise to a 0° C.solution of lithio 3-phenyl-1,2-oxazole-5-carboxylate (190 mg, 0.97mmol, 1.00 equiv),[1-[trans-3-aminocyclobutyl]-1H-1,2,3-triazol-5-yl]methanolhydrochloride (204 mg, 1.00 mmol, 1.00 equiv) and HATU (684 mg, 1.80mmol, 1.80 equiv) in DMF (5 mL). The resulting solution was stirred for1 hour at room temperature and diluted with 50 mL of water/ice. Theresulting solution was extracted with ethyl acetate (3×50 mL) and theorganic layers combined. The resulting mixture was washed with brine(2×30 mL), dried over anhydrous sodium sulfate and concentrated undervacuum. The crude product was purified by Flash-Prep-HPLC with thefollowing conditions (IntelFlash-1): Column, C18; mobile phase,H₂O/CH₃CN=100:1 increasing to H₂O/CH₃CN=1:100 within 30 min; Detector,UV 254 nm to give 100 mg (30%) of3-phenyl-N-[trans-3-[5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LC-MS (ES, m/z): [M+1]⁺=340. ¹H NMR (400 MHz,DMSO-d₆): δ 9.54-9.52 (d, J=7.2 Hz, 1H), 7.96-7.94 (m, 2H), 7.69-7.63(m, 2H), 7.56-7.54 (m, 3H), 5.45-5.42 (t, J=5.6 Hz, 1H), 5.27-5.20 (m,1H), 4.80-4.71 (m, 1H), 4.56-4.55 (d, J=5.6 Hz, 2H), 2.93-2.87 (m, 2H),2.81-2.75 (m, 2H).

Example 6N-(trans-3-(5((R)-1-hydroxyethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1a: methyl (2R)-2-[(tert-butyldimethylsilyl)oxy]propanoate: into a250-mL round-bottom flask, was placed a solution of methyl(2R)-2-hydroxypropanoate (5 g, 48.03 mmol, 1.00 equiv) and imidazole(6.5 g, 95.59 mmol, 2.00 equiv) in dichloromethane (100 mL). This wasfollowed by the addition of a solution oftert-butyl(chloro)dimethylsilane (8.7 g, 57.72 mmol, 1.20 equiv) indichloromethane (50 mL) dropwise with stirring at 0° C. The resultingsolution was stirred for 2 hours at room temperature. The reaction wasthen quenched by the addition of 100 mL of water/ice. The resultingsolution was extracted with dichloromethane (3×100 mL) and the organiclayers combined. The resulting mixture was washed with brine (3×50 mL),dried over anhydrous sodium sulfate and concentrated under vacuum togive 7 g (67%) of methyl (2R)-2-[(tert-butyldimethylsilyl)oxy]propanoateas colorless oil.

Step 1b: (2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazide: into a250-mL round-bottom flask, was placed a solution of methyl(2R)-2-[(tert-butyldimethylsilyl)oxy]propanoate (7 g, 32.06 mmol, 1.00equiv) in ethanol (100 mL). To the solution was added hydrazine (10 g,159.81 mmol, 5.00 equiv, 80%). The resulting solution was stirred for 15hours at 90° C. in an oil bath. The resulting solution was quenched bythe addition of water/ice. The resulting solution was extracted withethyl acetate (3×100 mL) and the organic layers combined. The resultingmixture was washed with brine (2×100 mL), dried over anhydrous sodiumsulfate and concentrated under vacuum to give 6.5 g (93%) of(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazide as colorless oil.LC-MS (ES, m/z): [M+1]⁺=219.

Step 1: methyl(trans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylate:into a 250-mL round-bottom flask, under nitrogen, was placed a solutionof methyl 3-cis-hydroxycyclobutane-1-carboxylate (8 g, 61.47 mmol, 1.00equiv), 2,3-dihydro-1H-isoindole-1,3-dione (18.1 g, 123.02 mmol, 2.00equiv) and triphenylphosphine (32.3 g, 123.15 mmol, 2.00 equiv) in THF(100 mL). This was followed by the addition of DIAD (24.9 g, 123.14mmol, 2.00 equiv) dropwise with stirring at 0° C. The resulting solutionwas stirred for 2.5 hours at room temperature. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:5). The crude product wasre-crystallized from petroleum ether/ethyl acetate in the ratio of 10:1to give 7.2 g (45%) of methyltrans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylateas a white solid. LC-MS (ES, m/z): [M+1]⁺=260. ¹H-NMR (400 MHz, CDCl₃):δ 7.85-7.82 (m, 2H), 7.74-7.71 (m, 2H), 5.08-5.04 (m, 1H), 3.75 (s, 3H),3.34-3.32 (m, 1H), 3.20-3.12 (m, 2H), 2.66-2.60 (m, 2H).

Step 2:trans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylicacid: into a 100-mL round-bottom flask, was placed a solution of methyltrans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylate(7.2 g, 27.77 mmol, 1.00 equiv) in 1,4-dioxane (100 mL). To the solutionwas added 5M hydrogen chloride aqueous (10 mL). The resulting solutionwas stirred for 4 hours at 80° C. in an oil bath. The resulting mixturewas concentrated under vacuum to give 6.2 g (91%) oftrans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylicacid as a white solid. LC-MS (ES, m/z): [M−1]⁻=244.

Step 3:(2R)-2-[(tert-butyldimethylsilyl)oxy]-N-[trans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutyl]carbonyl]propanehydrazide:into a 250-mL round-bottom flask, was placed a solution oftrans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylicacid (6.2 g, 25.28 mmol, 1.00 equiv),(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazide (6.61 g, 30.27mmol, 1.20 equiv) and HATU (14.4 g, 37.89 mmol, 1.50 equiv) in THF (100mL). This was followed by the addition of DIEA (9.81 g, 75.91 mmol, 3.00equiv) dropwise with stirring at 0° C. The resulting solution wasstirred for 1 hour at room temperature. The reaction was then quenchedby the addition of 100 mL of water/ice. The resulting solution wasextracted with ethyl acetate (3×50 mL) and the organic layers combined.The resulting mixture was washed with brine (2×50 mL), dried overanhydrous sodium sulfate and concentrated under vacuum. The residue wasapplied onto a silica gel column with ethyl acetate/petroleum ether(1:4) to give 7 g (62%) of(2R)-2-[(tert-butyldimethylsilyl)oxy]-N-[trans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutyl]carbonyl]propanehydrazideas colorless oil. LC-MS (ES, m/z): [M+1]⁺=446.

Step 4:2-[trans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-2,3-dihydro-1H-isoindole-1,3-dione:into a 250-mL round-bottom flask, was placed a solution of(2R)-2-[(tert-butyldimethylsilyl)oxy]-N-[[trans-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutyl]carbonyl]propanehydrazide(6.95 g, 15.60 mmol, 1.00 equiv) and TEA (7.89 g, 77.97 mmol, 5.00equiv) in dichloromethane (100 mL). This was followed by the addition ofa solution of 4-methylbenzene-1-sulfonyl chloride (8.92 g, 46.79 mmol,3.00 equiv) in dichloromethane (50 mL) dropwise with stirring at 0° C.The resulting solution was stirred for 15 hours at room temperature. Thereaction was then quenched by the addition of 100 mL of water/ice. Theresulting solution was extracted with dichloromethane (2×50 mL) and theorganic layers combined. The resulting mixture was washed with brine(2×50 mL), dried over anhydrous sodium sulfate and concentrated undervacuum. The crude product was purified by Flash-Prep-HPLC with thefollowing conditions (IntelFlash-1): Column, C18; mobile phase,H₂O/CH₃CN=100:1 increasing to H₂O/CH₃CN=1:100 within 30 min; Detector,UV 254 nm to give 3.28 g (49%) of2-[trans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-2,3-dihydro-1H-isoindole-1,3-dioneas colorless oil. LC-MS (ES, m/z): [M+1]⁺=428. ¹H-NMR (400 MHz, CDCl₃):δ 7.72-7.70 (m, 2H), 7.60-7.58 (m, 2H), 5.04-4.96 (m, 2H), 3.83-3.78 (m,1H), 3.26-3.24 (m, 2H), 2.67-2.62 (m, 2H), 1.49-1.48 (d, J=6.8 Hz, 3H),0.76 (s, 9H), 0.01 (s, 3H), 0.00 (s, 3H).

Step 5:trans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutan-1-amine:into a 250-mL round-bottom flask, was placed a solution of2-[trans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-2,3-dihydro-1H-isoindole-1,3-dione(1.18 g, 2.76 mmol, 1.00 equiv) in ethanol (100 mL). To the solution wasadded hydrazine hydrate (3.45 g, 55.13 mmol, 20.00 equiv, 80%). Theresulting solution was stirred for 3 hours at room temperature. Thesolids were filtered and the resulting mixture concentrated under vacuumto give 760 mg (crude) oftrans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutan-1-amineas a colorless oil. LC-MS (ES, m/z): [M+1]⁺=298.

Step 6:N-(trans-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamide:into a 100-mL round-bottom flask, was placed a solution of lithio3-phenyl-1,2-oxazole-5-carboxylate (300 mg, 1.54 mmol, 1.20 equiv),3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutan-1-amine(380 mg, 1.28 mmol, 1.00 equiv) and HATU (728 mg, 1.92 mmol, 1.50 equiv)in THF (50 mL). This was followed by the addition of DIEA (500 mg, 3.87mmol, 3.00 equiv) dropwise with stirring at 0° C. The resulting solutionwas stirred for 1 hour at room temperature. The resulting solution wasdiluted with 50 mL of water/ice. The resulting solution was extractedwith ethyl acetate (3×50 mL) and the organic layers combined. Theresulting mixture was washed with brine (2×30 mL), dried over anhydroussodium sulfate and concentrated under vacuum to give 300 mg (50%) ofN-(trans-3-[5-[(1R)-1-](tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamideas an off-white crude solid. LC-MS (ES, m/z): [M+1]⁺=469.

Step 7:N-(trans-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamide:into a 50-mL round-bottom flask, was placed a solution ofN-(3-[trans-5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamide(300 mg, 0.64 mmol, 1.00 equiv) and TBAF (1 mol/L in tetrahydrofuran, 1mL) in THF (5 mL). The resulting solution was stirred for 3 hours atroom temperature, diluted with 20 mL of water. The resulting solutionwas extracted with ethyl acetate (3×30 mL) and the organic layerscombined. The resulting mixture was washed with brine (2×10 mL), driedover anhydrous sodium sulfate and concentrated under vacuum. The residuewas applied onto a silica gel column with dichloromethane/methanol(20:1). The crude product was purified by Flash-Prep-HPLC with thefollowing conditions (IntelFlash-1): Column, C18; mobile phase,H₂O/CH₃CN=100:1 increasing to H₂O/CH₃CN=1:100 within 30 min; Detector,UV 254 nm to give 149.2 mg (66%) ofN-(trans-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamide(Compound A) as a white solid. LC-MS (ES, m/z): [M+1]⁺=355. ¹H NMR (400MHz, DMSO-d₆): δ 9.48-9.46 (d, J=7.6 Hz, 1H), 7.96-7.93 (m, 2H), 7.67(s, 1H), 7.56-7.54 (m, 3H), 5.95-5.94 (d, J=5.6 Hz, 1H), 4.95-4.89 (m,1H), 4.73-4.63 (m, 1H), 3.77-3.71 (m, 1H), 2.73-2.50 (m, 4H), 1.50-1.48(d, J=6.8 Hz, 3H).

Example 7N-(3-(1-methyl-1H-pyrazol-5-yl)propyl)-3-phenylisoxazole-5-carboxamide

Step 1: Cyanomethyl triphenylphosphonium chloride: chloroacetonitrile(10 g, 0.132 mol) was added dropwise to a solution of triphenylphosphine(23.5 g, 0.0895 mol) in (120 mL) toluene and refluxed for 6 h. Thereaction mixture was cooled to room temperature and the solids werefiltered and washed with (2×20 mL) diethyl ether to give the product (15g, 49.58%) as a white solid. ¹H-NMR (400 MHz, DMSO) δ 8.02-7.97 (m, 3H),7.90-7.79 (m, 12H), 5.94 (s, 1H), 5.90 (s, 1H); LCMS [M+H]⁺ 301.7.

Step 2: 3-(2-Methyl-2H-pyrazol-3-yl)-acrylonitrile (4): To a stirredsolution of 2-Methyl-2H-pyrazole-3-carbaldehyde 3 (3.8 g, 0.0345 mol) intoluene (50 mL) was added cyanomethyl triphenylphosphonium chloride(12.8 g, 0.0389 mol) at room temperature. DBU (1.52 mL, 0.0099 mol) wasthen added dropwise and heated to reflux for 3 h. After completion ofthe reaction the toluene was distilled off completely under vacuum. Theresulting crude product was purified on combi flash chromatography (thedesired product eluting in 15% EtOAc:hexane) to afford the product (1.1g, 24.01% yield) as a white solid. ¹H NMR (400 MHz, CDCl₃) δppm:7.46-7.45 (d, J=176 Hz, 1H), 7.3-7.25 (m, 1H), 6.56(s, 1H), 5.79-5.75(d, J=16.34 Hz, 1H), 3.93 (s, 3H). LCMS [M+H]⁺: 134.1.

Step 3: 3-(1-methyl-1H-pyrazol-5-yl)propan-1-amine: Raney Ni (1 g, 50%in water suspension) was added to a solution of3-(2-methyl-2H-pyrazol-3-yl)-acrylonitrile (1.0 g, 0.0075 mol) inethanol (10 mL)at room temperature. The reaction mixture was thenstirred under a hydrogen atmosphere for 16 h, filtered through a celitebed and was washed with ethanol (2×10 mL). The filtrate was evaporatedunder vacuum to afford the compound (0.9 g, 86.53% yield) as a yellowoil. The crude product was used directly for amide coupling.

Step 4:N-(3-(1-methyl-1H-pyrazol-5-yl)propyl)-3-phenylisoxazole-5-carboxamide:EDC.HCl (0.220g, 0.00115 mole), HOBt.H₂O (0.129 g, 0.00084 mole) wereadded to a solution of 3-phenylisoxazole-5-carboxylic acid (0.150g,0.00076 mol) in THF (5 mL) and stirred at room temperature for 20minutes. To this reaction mixture was added3-(1-methyl-1H-pyrazol-5-yl)propan-1-amine (0.16g, 0.00115mol) and DIPEA(0.590 mL, 0.0023 mole) and stirred for 16 h. The reaction mixture wasconcentrated on rotary evaporator and the mixture was purified usingcombiflash, desired product eluted in 35% EtOAc:hexane (0.115g, 47.23%)as an off white solid. ¹H NMR (400 MHz, CDCl₃) δ 7.54-7.53 (m, 1H),7.50-7.48 (m, 1H), 7.38-7.37 (d, J=1.84 Hz 1H), 7.15-7.14 (m, 1H), 6.88(br, 1H), 6.81 (s, 1H), 3.79 (s, 3H), 3.56-3.51 (q, 2H), 2.71-2.67 (t,2H), 2.02-1.95 (m, 2H); LCMS [M+H]⁺316.9; HPLC purity: 95.83% at 220 nmand 98.85% at 254 nm.

Example 8 N-(2-methoxyethyl)-4-phenylfuran-2-carboxamide

Compound 8 was obtained as an off white solid using the generalprocedure 1. Yield: 57%; ¹H-NMR (400 MHz, DMSO-d₆) δ 8.42 (br, 1H), 8.35(s, 1H), 7.66 (d, J=7.6 Hz, 2H), 7.57 (s, 1H), 7.42 (t, J=7.6 Hz, 2H),7.31 (t, J=7.3 Hz, 1H), 3.44-3.39 (m, 4H), 3.26 (s, 3H); LC-MS: (M+H)⁺246.0; HPLC purity 99.32% at 220 nm and 99.35% at 254 nm.

Example 9 4-phenyl-N-((tetrahydrofuran-2-yl)methyl)furan-2-carboxamide:

Compound 9 was obtained as an off white solid using the generalprocedure 1. Yield: 46%; ¹H-NMR (400 MHz, DMSO-d₆) δ 8.42 (br, 1H), 8.35(s, 1H), 7.66 (d, J=7.6 Hz, 2H), 7.59 (s, 1H), 7.42 (t, J=7.2 Hz, 2H),7.31 (t, J=7.2 Hz, 1H), 3.97 (m, 1H), 3.79 (m, 1H), 3.64 (m, 1H), 3.27(s, 2H), 1.90-1.78 (m, 3H), 1.61 (m, 1H); LC-MS: (M+H)⁺ 271.9; HPLCpurity 98.21% at 220 nm and 98.35% at 254 nm.

Example 10 N-(2-morpholinoethyl)-4-phenylfuran-2-carboxamide

Compound 10 was obtained as an off white solid using the generalprocedure 1. Yield: 42%; ¹H-NMR (400 MHz, DMSO-d₆) δ 8.35 (m, 2H), 7.67(d, J=7.6 Hz, 2H), 7.54 (s, 1H), 7.42 (t, J=7.2 Hz, 2H), 7.31 (t, J=7.2Hz, 1H), 3.56 (s, 4H), 3.36 (s, 2H), 2.46-2.40 (m, 6H); LC-MS: (M+H)⁺300.7; HPLC purity 99.42% at 220 nm and 99.36% at 254 nm.

Example 11 N-(3-(1H-imidazol-1-yl)propyl)-4-phenylfuran-2-carboxamide

Compound 11 was obtained as an off white solid using the generalprocedure 1. Yield: 33%; ¹H-NMR (400 MHz, DMSO-d₆) δ 8.54 (t, J=5.6 Hz,1H), 8.36 (s, 1H), 7.67 (d, J =7.2 Hz, 2H), 7.56 (s, 1H), 7.43 (t, J=7.2Hz, 2H), 7.31 (t, J=7.2 Hz, 1H), 7.21 (s, 1H), 6.89 (s, 1H), 4.02 (t,J=6.8 Hz, 2H), 3.23 (q, J=6.8 Hz, 2H), 1.97 (quintet, J=6.8 Hz, 2H);LC-MS: (M+H)⁺ 296.1; HPLC purity 99.51% at 220 nm and 99.21% at 254 nm.

Example 12 N-cyclopropyl-4-phenylfuran-2-carboxamide

Compound 12 was obtained as an off white solid using the generalprocedure 1 (0.032 g, 19.04%); ¹H NMR (400 MHz, CDCl₃) δ 7.666 (s, 1H),7.48-7.46 (m, 2H), 7.41-7.36 (m, 3H), 7.31-7.24 (m, 1H), 6.44 (s, 1H),2.89-2.85 (m, 1H), 0.89-0.84 (m, 2H), 0.65-0.61 (m, 2H); LCMS [M+H]⁺228.1; HPLC purity: 99.57% at 220 nm and 99.02% at 254 nm.

Example 13N-(trans-3-(5-(1-(methylsulfonyl)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1:N-trans-(3-[[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazido]carbonyl]cyclobutyl)-3-phenylisoxazole-5-carboxamide:T₃P (50%) (55.6 g, 5.00 eq.), TEA (8.83 g, 87.26 mmol, 5.00 eq.) and(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazide (4.95 g, 22.67mmol, 1.30 eq.) were added to a solution of3-(3-phenylisoxazole-5-amido)cyclobutane-1-carboxylic acid (5 g, 17.47mmol, 1.00 eq.) in tetrahydrofuran (50 mL) and the solution was stirredfor 1.5 hours at 30° C. The reaction was then quenched by the additionof water, extracted with dichloromethane and the organic layerscombined, dried and concentrated under vacuum. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:1) togive 8.45 g (crude) ofN-trans-(3-[[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazido]carbonyl]cyclobutyl)-3-phenylisoxazole-5-carboxamideas a light yellow solid; LC-MS (ES, m/z): [M+1]⁺=487.1.

Step 2:N-trans-(3-[5-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide:I₂ (20.74 g, 5.00 eq.) and TEA (9.98 g, 98.63 mmol, 6.00 eq.) were addedto a solution of Ph₃P (21.56 g, 5.00 eq.) in dichloromethane (50 mL),followed by the dropwise addition of a solution ofN-trans-(3-[[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazido]carbonyl]cyclobutyl)-3-phenylisoxazole-5-carboxamide(8 g, 16.44 mmol, 1.00 eq.) in dichloromethane (50 mL). The resultingsolution was stirred for 2.5 hours at 0° C., then quenched by theaddition of water, and the solution was extracted with dichloromethaneand the organic layers combined, dried and concentrated under vacuum toafford 3.19 g (41%) ofN-trans-(3-[5-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamideas a brown solid; LC-MS (ES, m/z): [M+1]⁺=469.1.

Step 3:N-trans-(3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution ofN-trans-(3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide(25.3 g, 53.99 mmol, 1.00 eq.) and pyridine hydrofluoride (15 g, 151.35mmol, 2.80 eq.) in methanol (50 mL) was stirred for 5 hours at roomtemperature. The reaction was then quenched by the addition of water,extracted with dichloromethane and the organic layers combined, driedand concentrated under vacuum. The residue was dissolved in 50 mL oftoluene and the solids were collected by filtration to give 1.85 g (10%)ofN-trans-(3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamideas a yellow solid; LC-MS (ES, m/z): [M+1]⁺=355.0.

Step 4:(R)-1-[5-trans-[3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethylmethanesulfonate: TEA (1.28 g, 12.65 mmol, 3.00 eq.) and MsCl (0.725 g,1.50 eq.) were added to a solution ofN-trans-(3-[5-[(R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide(1.5 g, 4.23 mmol, 1.00 eq.) in dichloromethane (50 mL) and the solutionwas stirred for 3 hours at 0° C. The reaction was then quenched by theaddition of 200 mL of saturation NH₄Cl, extracted with dichloromethaneand the organic layers combined, dried and concentrated under vacuum togive 1.72 g (94%) of(R)-1-[5-trans-[3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethylmethanesulfonate as a yellow solid; LC-MS (ES, m/z): [M+1]⁺=433.0.

Step 5:N-trans-(3-[5-[1-(methylsulfanyl)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution of(R)-1-[5-trans-[3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethylmethanesulfonate (400 mg, 0.92 mmol, 1.00 eq.) and NaMeS (132 mg, 2.00eq.) in DMF (3 mL) was stirred for 5 hours at 100° C. The resultingmixture was concentrated under vacuum and the residue was applied onto asilica gel column with ethyl acetate/petroleum ether (4:5) to give 254mg (71%) ofN-trans-(3-[5-[1-(methylsulfanyl)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamideas a yellow solid; LC-MS (ES, m/z): [M+1]⁺=385.0.

Step 6:N-(3-[5-trans-[1-methanesulfonylethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution ofN-(3-[5-trans-[1-(methylsulfanyl)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamide(230 mg, 0.60 mmol, 1.00 eq.) and MCPBA (0.42 g, 4.00 eq.) indichloromethane (5 mL) was stirred for 2 hours at room temperature. Theresulting mixture was concentrated under vacuum and the residue wasapplied onto a silica gel column with dichloromethane/methanol (25:1) togive 80 mg (32%) of a racemic mixture ofN-(3-[5-trans-[1-methanesulfonylethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl)-3-phenylisoxazole-5-carboxamideas a yellow solid; LC-MS (ES, m/z): [M+1]⁺=417.0 ¹H NMR (DMSO-d₆, 400MHz, ppm): δ 9.44 (s, 1H), 7.93-7.91 (m, 2H), 7.65 (s,1H), 7.54-7.52 (m,3H), 5.16-5.11 (m, 1H), 4.69-4.63 (m, 1H), 3.78-3.75 (m, 1H), 3.14 (s,3H), 2.72-2.65 (m, 4H), 1.74-1.70 (m, 3H); HPLC purity: 97.1% at 254 nm.

Example 14N-(trans-3-(5-((R)-1-methoxyethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1:3-phenyl-N-[trans-3-[N-[(2R)-2-methoxypropanoyl]hydrazinecarbonyl]cyclobutyl]-1,2-oxazole-5-carboxamide:TEA (315 mg, 3.11 mmol, 2.97 eq.) and T₃P (667 mg) were added to asolution of trans-3-(3-phenylisoxazole-5-amido)cyclobutane-1-carboxylicacid (300 mg, 1.05 mmol, 1.00 eq.) and (2R)-2-methoxypropanehydrazide(185 mg, 1.57 mmol, 1.49 eq.) in tetrahydrofuran (5 mL) and the mixturewas stirred for 2 hours at room temperature. The resulting mixture wasconcentrated under vacuum, diluted with 5 mL of methanol. The solidswere collected by filtration and dried in an oven under reduced pressureto give 200 mg (49%) of3-phenyl-N-[trans-3-[N-[(2R)-2-methoxypropanoyl]hydrazinecarbonyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LC-MS (ES, m/z): [M+1]⁺=387.2.

Step 2:3-phenyl-N-[trans-3-[5-[(1S)-1-methoxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide:3-phenyl-N-[trans-3-[N-[(2R)-2-methoxypropanoyl]hydrazinecarbonyl]cyclobutyl]-1,2-oxazole-5-carboxamide(150 mg, 0.39 mmol, 1.00 eq.) was added to a solution of PPh₃ (150 mg,0.57 mmol, 1.47 eq.), I₂ (150 mg) and TEA (120 mg, 1.19 mmol, 3.05 eq.)in dichloromethane (5 mL) and the mixture was stirred for 2 hours at 0°C. The resulting mixture was washed with water (2×5 mL) and concentratedunder vacuum. The crude product was purified by Prep-HPLC with thefollowing conditions: (Waters): Column: XBridge C18 OBD Prep Column 10λm, 19 mm×250 mm; mobile phase, water (0.5% NH₄HCO₃) and CH₃CN;Gradient; 40% of CH₃CN to 45% of CH₃CN in 10 min; Detector, UV 254 nm togive 101.8 mg (71%) of3-phenyl-N-[trans-3-[5-[(1S)-1-methoxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid. LC-MS (ES, m/z): [M+1]⁺=369.0; ¹H NMR (DMSO-d₆,300 MHz, ppm): δ 9.46-9.44 (d, J=7.2 Hz, 1H), 7.94-7.93 (m, 2H), 7.66(s, 1H), 7.55-7.54 (m, 3H), 4.72-4.64 (m, 2H), 3.78-3.73 (m, 1H), 3.29(s, 3H), 2.73-2.61 (m, 4H), 1.51-1.49 (d, J=6.8 Hz, 3H); HPLC purity:99.1% at 254 nm.

Example 15 and 163-phenyl-N-(trans-3-(5((S)-1-(2,2,2-trifluoroethoxy)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)isoxazole-5-carboxamideand3-phenyl-N-(trans-3-(5((R)-1-(2,2,2-trifluoroethoxy)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)isoxazole-5-carboxamide

2,2,2-trifluoroethyl trifluoromethanesulfonate (491 mg, 2.12 mmol, 1.50eq.) was added to a solution of3-phenyl-N-[trans-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamide(500 mg, 1.41 mmol, 1.00 eq.) and sodium hydride (85 mg, 2.12 mmol, 1.50eq.) in DMF (10 mL) and the solution was stirred for 2 hours at roomtemperature. The reaction mixture was diluted with water (30 mL),extracted with ethyl acetate (3×30 mL) and the organic layers werecombined, dried over anhydrous sodium sulfate and concentrated undervacuum. The crude product was purified by Prep-HPLC with the followingconditions (Waters): Column: XBridge C18 OBD Prep Column 10 μm, 19mm×250 mm; Mobile Phase A: water (10 mmol/L NH₄HCO₃), Mobile Phase B:ACN; Flow rate: 25 mL/min; Gradient: 15% B to 65% B in 8 min; 254/220nm. The isomers were purified by Chiral-Prep-HPLC with the followingconditions: Column: Chiralpak IA 2*25 cm, 5 um; Mobile Phase A: Hexane;HPLC, Mobile Phase B: EtOH, HPLC Flow rate: 18 mL/min; Gradient: 40 B to40 B in 15 min; 254/220 nm; RT1: 9.505; RT2: 11.208. This resulted in19.1 mg (3%) of front peak as a white solid and 16.8 mg of second peakas a white solid.

Front Peak: LC-MS (ES, m/z): [M+1]⁺=437.1. ¹H-NMR (DMSO-d₆, 300 MHz,ppm): δ 7.87-7.86 (m, 2H), 7.49-7.47 (m, 3H), 7.37 (s, 1H), 5.00-4.94(m, 1H), 4.11-4.02 (m, 2H), 3.81-3.74 (m, 1H), 2.78-2.68 (m, 4H),1.64-1.62 (d, J=6.6 Hz, 3H); HPLC purity: 98.6% at 254 nm.

Second Peak: LC-MS (ES, m/z): [M+1]⁺=437.1; ¹H NMR (DMSO-d₆, 300 MHz,ppm): δ 7.86 (br, 2H), 7.48 (br, 3H), 7.37 (s, 1H), 5.00-4.94 (m, 1H),4.10-4.02 (m, 2H), 3.79-3.77 (m, 1H), 2.78-2.69 (m, 4H), 1.64-1.62 (d,J=6.6 Hz, 3H); HPLC purity: 98.9% at 254 nm.

Example 17N-(trans-3-(5-(1-cyclobutoxyethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Sodium hydride (84 mg, 2.10 mmol, 3.00 eq.) was added in portions to acold (0° C.) solution of cyclobutanol (150 mg, 2.08 mmol, 3.00 eq.) inDMF (10 mL) and the resulting solution was stirred for 30 min at 0° C.(R)-1-[5-trans-[3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethylmethanesulfonate (300 mg, 0.69 mmol, 1.00 eq.) was added to the mixtureand stirred for an additional 2 hours at 25° C. The reaction was thenquenched by the addition of 100 mL of water, extracted with ethylacetate (2×100 mL) and the organic layers combined. The resultingmixture was washed with brine (2×100 mL), dried over anhydrous sodiumsulfate and concentrated under vacuum. The crude product was purified byPrep-TLC (petroleum ether:ethyl acetate=1:1) to give 50.2 mg (18%) of3-phenyl-N-[trans-3-[5-(1-cyclobutoxyethyl)-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=409.4; ¹H NMR (300 MHz,DMSO-d₆) 6 9.46-9.43 (d, J=7.2 Hz, 1H), 7.95-7.92 (m, 2H), 7.65 (s, 1H),7.56-7.54 (m, 3H), 4.78-4.64 (m, 2H), 4.04-3.99 (m, 1H), 3.77-3.74 (m,1H), 2.71-2.50 (m, 4H), 2.18-2.14 (m, 1H), 1.97-1.85 (m, 2H), 1.75-1.57(m, 2H), 1.49-1.47 (d, J=6.6 Hz, 3H), 1.47-1.40 (m, 1H); HPLC purity:98.0% at 254 nm.

Example 18N-(trans-3-(5-(1-(cyclobutylmethoxy)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

(Bromomethyl)cyclobutane (83 mg, 0.56 mmol, 2.00 eq.) was added to asolution of3-phenyl-N-[trans-3-[5-(1-hydroxyethyl)-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamide(100 mg, 0.28 mmol, 1.00 eq.) and sodium hydride (17 mg, 0.42 mmol, 1.50eq.) in DMF (2 mL). The resulting solution was stirred for 2 hours atroom temperature, the reaction mixture was quenched by the addition ofwater (20 mL) and the solution was extracted with ethyl acetate (3×10mL). The organic layers were combined and dried over anhydrous sodiumsulfate and concentrated under vacuum. The crude product was purified byPrep-HPLC with the following conditions (Waters): Column: XBridge PrepC18 OBD Column 19×150 mm, 5 um; Mobile Phase A: water (10 mmol/LNH₄HCO₃), Mobile Phase B: ACN; Flow rate: 20 ml/min; Gradient: 40% B to80% B in 8 min; 254 nm to give 21.2 mg (18%) of3-phenyl-N-[trans-3-[5-[1-(cyclobutylmethoxy)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+1]⁺=421.0; ¹H NMR (DMSO-d₆, 300MHz, ppm): δ 9.46-9.43 (d, J=7.2 Hz, 1H), 7.94-7.93 (m, 2H), 7.66 (s,1H), 7.57-7.54 (m, 3H), 4.81-4.74 (m, 1H), 4.72-4.64 (m, 1H), 3.77-3.74(m, 1H), 3.49-3.36 (m, 2H), 2.70-2.65 (m, 4H), 1.96-1.91 (m, 2H),1.88-1.80 (m, 2H), 1.75-1.67 (m, 2H), 1.50-1.48 (d, J=6.6 Hz, 3H); HPLCpurity: 99.8% at 254 nm.

Example 19N-(trans-3-(5-(1-(oxetan-3-ylmethoxy)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

The title compound was prepared using the method shown in example 18.

Example 20N-(trans-3-(5-((R)-1-((1-methylazetidin-3-yl)methoxy)ethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: tert-butyl3-[(methanesulfonyloxy)methyl]azetidine-1-carboxylate: MsCl (549 mg,4.82 mmol, 1.20 eq.) and TEA (606 mg, 6.00 mmol, 1.50 eq.) were added toa solution of tert-butyl 3-(hydroxymethyl)azetidine-1-carboxylate (750mg, 4.01 mmol, 1.00 eq.) in dichloromethane (20 mL) and the solution wasstirred for 3 hours at room temperature. The resulting solution wasdiluted with ethyl acetate (50 mL), washed with saturated sodiumcarbonate aq. (1×30 mL), water (1×30 mL), dried over anhydrous sodiumsulfate and concentrated under vacuum to give 980 mg (92%) of tert-butyl3-[(methanesulfonyloxy)methyl]azetidine-1-carboxylate as colorless oil.

Step 2: tert-butyl3-[(1-[5-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethoxy)methyl]azetidine-1-carboxylate:tert-butyl 3-[(methanesulfonyloxy)methyl]azetidine-1-carboxylate (670mg, 2.53 mmol, 1.50 eq.) was added to a solution of3-phenyl-N-[trans-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamide(600 mg, 1.69 mmol, 1.00 eq.) and t-BuOK (570 mg, 5.08 mmol, 3.00 eq.)in THF (15 mL). The reaction was stirred for 16 hours at 80° C. in anoil bath then diluted with ethyl acetate (100 mL). The resultingsolution was washed with water (2×30 mL), brine (1×30 mL), dried overanhydrous sodium sulfate and concentrated under vacuum. The residue wasapplied onto a silica gel column with ethyl acetate/petroleum ether(1:10 up to 1:2) to give 287 mg (32%) of tert-butyl3-[(1-[5-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl]ethoxy)methyl]azetidine-1-carboxylateas a light yellow solid; LC-MS (ES, m/z): [M+H]⁺=524.2.

Step 3:3-phenyl-N-[trans-3-[5-[1-(azetidin-3-ylmethoxy)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamide:a solution of tert-butyl3-[(1-[5-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1,3,4-oxadiazol-2-yl[ethoxy)methyl]azetidine-1-carboxylate(237 mg, 0.45 mmol, 1.00 eq.) and TFA (1.5 mL) in DCM (4 mL) was stirredfor 2 hours at room temperature. The reaction was quenched by additionof 20 mL of saturated sodium carbonate aqueous and extracted with ethylacetate (2×50 mL). The combined organic layer was washed with water(1×10 mL), brine (1×10 mL), dried over anhydrous sodium sulfate andconcentrated under vacuum to give 150 mg (78%) of3-phenyl-N-[trans-3-[5-[1-(azetidin-3-ylmethoxy)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamideas a yellow solid; LC-MS (ES, m/z): [M+H]⁺=424.2.

Step 4:3-phenyl-N-[trans3-(5-[1-[(1-methylazetidin-3-yl)methoxy]ethyl]-1,3,4-oxadiazol-2-yl)cyclobutyl]-isoxazole-5-carboxamide:HCHO (57 mg, 0.70 mmol, 1.50 eq.) was added to a solution of3-phenyl-N-[trans-3-[5-[1-(azetidin-3-ylmethoxy)ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamide(150 mg, 0.35 mmol, 1.00 eq.) in methanol (3 mL) and stirred for 30 min.NaBH(OAc)₃ (150 mg, 0.71 mmol, 2.00 eq.) was added to the reactionmixture and stirred16 hours at room temperature. After removing thesolid by filtration, the crude product (3 mL) was purified by Prep-HPLCwith the following conditions (Waters): Column: XBridge C18 OBD PrepColumn 10 μm, 19 mm×250 mm; Mobile Phase A: water (10 mmol/L NH₄HCO₃),Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 15% B to 45% B in 8min; 220/254 nm to give 68.6 mg (44%) of3-phenyl-N-[trans3-(5-[1-[(1-methylazetidin-3-yl)methoxy]ethyl]-1,3,4-oxadiazol-2-yl)cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=438.2; ¹H NMR (CDOD, 400 MHz):δ 7.89-7.87 (m, 2H), 7.51-7.50 (m, 3H), 7.39 (s, 1H), 4.85-4.78 (m, 2H),3.85-3.59 (m, 3H), 3.48-3.43 (m, 2H), 3.16-3.11 (m, 2H), 2.87-2.73 (m,4H), 2.60-2.57 (m, 1H), 2.35-2.33 (m, 3H), 1.61-1.58 (m, 3H); HPLCpurity: 97% at 254 nm.

Example 21N-(trans-3-(5-(1-methylazetidin-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamidetrifluoroacetate

Step 1:3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]isoxazole-5-carboxamide:a solution oftrans-3-(3-phenylisoxazole-5-amido)cyclobutane-1-carboxylic acid (1.706g, 5.96 mmol, 1.00 eq.) and CDI (1.933 g, 11.92 mmol, 2.00 eq.) intetrahydrofuran (30 mL) was stirred for 0.5 hour at room temperature.Hydrazine hydrate (1.118 g, 22.33 mmol, 3.75 eq.) was added to thereaction mixture and stirred for 2 hours at room temperature. Theproduct was precipitated by the addition of water and collected byfiltration to give 780 mg (44%) of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=301.2.

Step 2:3-phenyl-N-[trans-3-[[(1-methylazetidin-3-yl)formohydrazido]carbonyl]cyclobutyl]-isoxazole-5-carboxamide:1-methylazetidine-3-carboxylic acid (172.5 mg, 1.50 mmol, 1.50 eq.),HATU (570 mg, 1.50 mmol, 1.50 eq.) and DIEA (387 mg, 2.99 mmol, 3.00eq.) were added to a solution of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]-isoxazole-5-carboxamide(300 mg, 1.00 mmol, 1.00 eq.) in DMF (10 mL) and then stirred for 2hours at room temperature. The crude product was purified byFlash-Prep-HPLC with the following conditions (IntelFlash-1): Column,C18; mobile phase, MeCN/H₂O=5:95 increasing to MeCN/H₂O=95:5 within 30min; Detector, UV 254 nm to give 200 mg (50%) of3-phenyl-N-[trans-3-[[(1-methylazetidin-3-yl)formohydrazido]carbonyl]cyclobutyl]-isoxazole-5-carboxamideas an off-white solid; LC-MS (ES, m/z): [M+H]⁺=398.0.

Step 3:3-phenyl-N-[trans-3-[5-(1-methylazetidin-3-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamide:I₂ (232 mg) and TEA (276 mg, 2.73 mmol, 5.99 eq.) were added to a cold(0° C.) solution of PPh₃ (239 mg, 0.91 mmol, 2.00 eq.) in DCM (20 mL).To the mixture was added3-phenyl-N-[trans-3-[[(1-methylazetidin-3-yl)formohydrazido]carbonyl]cyclobutyl]-isoxazole-5-carboxamide(181 mg, 0.46 mmol, 1.00 eq.) at 0° C. The resulting solution wasstirred for 3 hours at room temperature, diluted with 50 mL of DCM,washed with NaHSO₃ aqueous (2×50 mL) and concentrated under vacuum. Theresidue was applied onto a Prep-TLC with ethyl acetate/petroleum ether(1:1). The resulting crude product was purified by Prep-HPLC with thefollowing conditions (HPLC-10): Column: XBridge C18 OBD Prep Column 100Å, 10 μm, 19 mm×250 mm; Mobile Phase A: water (10 mmol/L NH₄HCO₃),Mobile Phase B: ACN; Flow rate: 20 ml/min; Gradient: 20% B to 30% B in10 min; 254&220 nm to give 50 mg (29%) of3-phenyl-N-[trans-3-[5-(1-methylazetidin-3-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamideas a yellow solid; LC-MS (ES, m/z): [M−TFA+H]⁺=380.1; ¹H NMR (300 MHz,DMSO-d₆, ppm): δ 10.19-10.12 (m, 1H), 9.49-9.47 (d, J=7.5 Hz, 1H),7.95-7.92 (m, 2H), 7.66-7.64 (d, J=8.1 Hz, 1H), 7.56-7.54 (t, J=3.3 Hz,3H), 4.75-4.62 (m, 6H), 3.78-3.69 (m, 1H), 2.94 (s, 3H), 2.44-2.72 (m,4H); HPLC purity: 97.1% at 254 nm.

Example 22N-trans-3-(5-(oxetan-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1:3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]isoxazole-5-carboxamide:CDI (2.26 g, 13.94 mmol, 2.00 eq.) was added to a solution ofN-trans-3-(3-phenylisoxazole-5-amido)cyclobutane-1-carboxylic acid(prepared according to procedure shown in example 13, 2 g, 6.99 mmol1.00 eq.) in THF (3mL) and the solution was stirred for 1 hour at roomtemperature, followed by the addition of hydrazine hydrate (1.33 g,21.25 mmol, 3.00 eq., 80%). The resulting solution was stirred foradditional 1 hour at room temperature and then quenched with water.After removing the solids by filtration, the resulting mixture wasconcentrated under vacuum and the residue was washed with 10 mL ofmethanol to give 960 mg (46%) of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=301.1.

Step 2:3-phenyl-N-[trans-3-[(oxetan-3-ylformohydrazido)carbonyl]cyclobutyl]isoxazole-5-carboxamide:oxetane-3-carboxylic acid (170 mg, 1.67 mmol, 1.00 eq.), T₃P (5.3 g,8.33 mmol, 5.00 eq., 50%) and TEA (838 mg, 8.3 mmol, 5.00 eq.) wereadded to a solution of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]isoxazole-5-carboxamide(500 mg, 1.66 mmol, 1.00 eq.) in THF (50 mL). The resulting solution wasstirred for 20 min at room temperature, then quenched by the addition of200 mL of water. The resulting solution was extracted withdichloromethane (3×200 mL) and the organic layers combined. Theresulting mixture was washed with brine, dried over anhydrous sodiumsulfate and concentrated under vacuum. The residue solid was washed with2 mL of methanol to afford 420 mg (66%) of3-phenyl-N-[trans-3-[(oxetan-3-ylformohydrazido)carbonyl]cyclobutyl]isoxazole-5-carboxamideas an off-white solid; LC-MS (ES, m/z): [M+H]⁺=385.0.

Step 3:3-phenyl-N-[trans-3-[5-(oxetan-3-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamide:I₂ (579 mg, 2.28 mmol, 2.50 eq.), TEA (598 mg, 5.91 mmol, 6.50 eq.) and3-phenyl-N-[trans-3-[(oxetan-3-ylformohydrazido)carbonyl]cyclobutyl]isoxazole-5-carboxamide(350 mg, 0.91 mmol, 1.00 eq.) were added to a cold solution of PPh₃ (597mg, 2.28 mmol, 2.50 eq.) in dichloromethane (30 mL) at 0° C. Theresulting solution was stirred for 1 hour at room temperature, thenquenched by the addition of water. The resulting solution was extractedwith ethyl acetate and the organic layers combined. The resultingmixture was washed with brine, dried over anhydrous sodium sulfate andconcentrated under vacuum. The residue was applied onto a silica gelcolumn with dichloromethane/methanol (10:1) to afford 100.4 mg (30%) of3-phenyl-N-[trans-3-[5-(oxetan-3-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=367.1; ¹H NMR (300 MHz,DMSO-d₆, ppm): δ 9.46-9.44 (d, 1H, J=7.5 Hz), 7.95-7.92 (m, 2H), 7.66(s, 1H), 7.56-7.54 (m, 3H), 4.95-4.90 (m, 2H), 4.83-4.79 (m, 2H) ,4.75-4.51 (m, 2H), 3.78-3.71 (m, 1H) , 2.70-2.65 (m, 4H); HPLC purity:96.5% at 254 nm.

Example 23N-(trans-3-(5-(1,1-dioxidothietan-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1:N-(trans-3-(2-(1,1-dioxidothietane-3-carbonyl)hydrazine-1-carbonyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution of thietane-3-carboxylic acid 1,1-dioxide (500 mg, 3.4 mmol,1.00 eq.),3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]-isoxazole-5-carboxamide(1.0 g, 3.4 mmol, 1.00 eq.), T₃P (10 mL) and TEA (4 mL) intetrahydrofuran (20 mL) was stirred for 1 hour at room temperature. Thereaction was then quenched by the addition of water and the solids werecollected by filtration to afford 30 mg (42%) ofN-(trans-3-(2-(1,1-dioxidothietane-3-carbonyl)hydrazine-1-carbonyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a light yellow solid. LC-MS (ES, m/z): [M+H⁺=433.1.

Step 2:N-(trans-3-(5-(1,1-dioxidothietan-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution ofN-(trans-3-(2-(1,1-dioxidothietane-3-carbonyl)hydrazine-1-carbonyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide(400 mg, 0.92 mmol, 1.00 eq.) in POCl₃ (8 mL) was stirred for 3 hours at100° C. in an oil bath. The reaction was then quenched by the additionof sodium bicarbonate aqueous/ice, extracted with ethyl acetate and theorganic layers combined. The resulting mixture was washed with water,dried over anhydrous sodium sulfate and concentrated under vacuum togive 105.8 mg (28%) ofN-(trans-3-(5-(1,1-dioxidothietan-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H⁺=415.2; ¹H NMR (DMSO-d₆, 400MHz): δ 9.46-9.42 (m, 1H), 7.95-7.91 (m, 2H), 7.66-7.65 (m, 1H),7.55-7.54 (m, 3H), 4.75-4.57 (m, 5H), 4.23-4.14 (m, 1H), 3.73-3.52 (m,1H), 2.70-2.66 (m, 4H); HPLC purity: 99.2% at 254 nm.

Example 24 and 25N-cis-(3-(5-(1-(1-methylpiperidin-4-yl)azetidin-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideand N-trans-(3-(5-(1-(1-methylpiperidin-4-yl)azetidin-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: benzyl 1-(1-methylpiperidin-4-yl)azetidine-3-carboxylate: asolution of trifluoroacetic acid benzyl azetidine-3-carboxylate (1.3 g,4.26 mmol, 1.00 eq.), 1-methylpiperidin-4-one (482 mg, 4.26 mmol, 1.10eq.) and acetic acid (255 mg, 4.25 mmol, 1.00 eq.) in DCE (20 mL) wasstirred for 30 min, followed by the addition of NaBH(OAc)₃ (1.44 g, 6.79mmol, 1.60 eq.). The resulting solution was stirred for 16 hours at roomtemperature. The reaction was then quenched by the addition of water,extracted with dichloromethane and the organic layers combined. Theorganic layer was washed with brine, dried over anhydrous sodium sulfateand concentrated under vacuum. The residue was applied onto a silica gelcolumn with DCM/MeOH (10:1) to give 830 mg (68%) of benzyl1-(1-methylpiperidin-4-yl)azetidine-3-carboxylate as yellow oil; LC-MS(ES, m/z): [M+H]⁺=289.2.

Step 2: 1-(1-methylpiperidin-4-yl)azetidine-3-carboxylic acid: Palladiumon carbon (100 mg) was added to a solution of benzyl1-(1-methylpiperidin-4-yl)azetidine-3-carboxylate (830 mg, 2.88 mmol,1.00 eq.) in methanol (20 mL), the solution was degassed and back filledwith hydrogen. The resulting solution was stirred for 2 hours at roomtemperature, and the solids were filtered out. The resulting mixture wasconcentrated under vacuum to give 570 mg (crude) of1-(1-methylpiperidin-4-yl)azetidine-3-carboxylic acid as light yellowoil; LC-MS (ES, m/z): [M+H]⁺=199.1.

Step 3:3-phenyl-N-[trans-3-([[1-(1-methylpiperidin-4-yl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamide:a solution of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]-isoxazole-5-carboxamide(409 mg, 1.36 mmol, 1.00 eq.),1-(1-methylpiperidin-4-yl)azetidine-3-carboxylic acid (270 mg, 1.36mmol, 1.00 eq.), T₃P (4.3 g, 6.76 mmol, 5.00 eq., 50%) and TEA (688 mg,6.80 mmol, 5.00 eq.) in tetrahydrofuran (10 mL) was stirred for 30 minat room temperature. The reaction was then quenched by the addition ofwater, extracted with ethyl acetate and the aqueous layers combined andconcentrated under vacuum. The crude product was purified byFlash-Prep-HPLC with the following conditions (IntelFlash-1): Column,C18; mobile phase, methanol/H₂O=5:95 increasing to methanol/H₂O=95:5within 30 min; Detector, UV 254 nm to give 220 mg (34%) of3-phenyl-N-[trans-3-([[1-(1-methylpiperidin-4-yl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamideas a light yellow solid; LC-MS (ES, m/z): [M+H]⁺=481.2.

Step 4: a solution of3-phenyl-N-[trans-3-([[1-(1-methylpiperidin-4-yl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamide(160 mg, 0.33 mmol, 1.00 eq.) in POCl₃ (8 mL) was stirred for 1 hour at100° C. The reaction was then quenched by the addition of water/ice, thepH value of the solution was adjusted to 8 with sodium bicarbonateaqueous. The resulting solution was extracted with dichloromethane andthe organic layers combined, washed with brine, dried and concentratedunder vacuum. The crude product was purified by Prep-HPLC with thefollowing conditions (HPLC-10): Column, XBridge Shield RP18 OBD Column,5 um, 19*150mm; mobile phase, water (0.05% NH₄HCO₃) and ACN (27.0% ACNup to 37.0% in 8 min); Detector, UV 254/220 nm to give 19.6 mg (13%) offront peak as a white solid and 4.2 mg (3%) of second peak as anoff-white solid.

Front Peak: LC-MS (ES, m/z): [M+H]⁺=463.2; ¹H NMR (300 MHz, DMSO-d₆,ppm): δ 9.45-9.43 (d, 1H, J=7.5 Hz), 7.95-7.92 (m, 2H), 7.66 (s, 1H),7.56-7.53 (m, 3H), 4.67-4.64 (m, 1H), 3.85-3.80 (m, 1H), 3.73-3.69(m,1H), 3.60-3.55 (m, 2H), 3.29-3.24 (m, 3H), 2.68-2.62 (m, 5H), 2.12 (s,3H), 2.04-1.98 (m, 1H), 1.91-1.84 (m, 2H), 1.62-1.58 (m, 2H), 1.21-1.11(m, 2H); HPLC purity: 97.8% at 254 nm.

Second Peak: LC-MS (ES, m/z): [M+H]⁺=463.2; ¹H NMR (300 MHz, DMSO-d₆,ppm): δ 9.47-9.44 (d, 1H, J=7.8 Hz), 7.95-7.92 (m, 2H), 7.66 (s, 1H),7.56-7.54 (m, 3H), 4.72-4.64 (m, 1H), 3.77-3.74 (m, 1H), 3.62 (s, 2H),3.29 (s, 3H), 2.71-2.66 (m, 6H), 2.40-2.30 (m, 1H), 2.12 (s, 3H),1.89-1.75 (m, 4H), 1.29-1.25 (m, 2H); HPLC purity: 95.1% at 254 nm.

Example 263-phenyl-N-(trans-3-(5-(1-(2,2,2-trifluoroethyl)azetidin-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)isoxazole-5-carboxamide

The title compound was prepared using a similar method as shown inexample 20.

Example 27N-(trans-3-(5-(1-(cyclobutylmethyl)azetidin-3-yl)-1,3,4-oxadiazol-2-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: 3-benzyl 1-tert-butyl azetidine-1,3-dicarboxylate: a solution of1-[(tert-butoxy)carbonyl]azetidine-3-carboxylic acid (5 g, 24.85 mmol,1.00 eq.), BnBr (4.65 g, 27.19 mmol, 1.10 eq.) and DBU (5.67 g, 37.24mmol, 1.50 eq.) in toluene (80 mL) was stirred for 4 hours at roomtemperature. The reaction was then quenched by the addition of water,extracted with ethyl acetate and the organic layers combined. Theresulting mixture was washed with brine, dried over anhydrous sodiumsulfate and concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:6) to give 5.4 g(75%) of 3-benzyl 1-tert-butyl azetidine-1,3-dicarboxylate as colorlessoil; LC-MS (ES, m/z): [M+H−Boc]⁺=192.0.

Step 2: 2,2,2-trifluoroacetic acid benzyl azetidine-3-carboxylate: asolution of 3-benzyl 1-tert-butyl azetidine-1,3-dicarboxylate (5.4 g,18.53 mmol, 1.00 eq.)) and trifluoroacetic acid (7 mL).indichloromethane (50 mL) was stirred overnight at room temperature. Theresulting mixture was concentrated under vacuum to give 7 g (crude) of2,2,2-trifluoroacetic acid benzyl azetidine-3-carboxylate as lightyellow oil; LC-MS (ES, m/z): [M+H−TFA]⁺=191.8.

Step 3: benzyl 1-(cyclobutylmethyl)azetidine-3-carboxylate: a solutionof 2,2,2-trifluoroacetic acid cyclohexylmethyl azetidine-3-carboxylate(1.3 g, 4.18 mmol, 1.00 eq.), cyclobutanecarboxaldehyde (358 mg, 4.26mmol, 1.00 eq.) and acetic acid (255 mg, 4.25 mmol, 1.00 eq.) in DCE (20mL) was stirred for 30 min, and then NaBH(OAc)₃ (1.44 g, 6.79 mmol, 1.60eq.) was added. The resulting solution was stirred for 2 hours at roomtemperature. The reaction was then quenched by the addition of water,extracted with dichloromethane and the organic layers combined. Theresulting mixture was washed with brine, dried over anhydrous sodiumsulfate and concentrated under vacuum. The residue was applied onto asilica gel column with dichloromethane/methanol (20:1) to give 650 mg(59%) of benzyl 1-(cyclobutylmethyl)azetidine-3-carboxylate as colorlessoil; LC-MS (ES, m/z): [M+H]⁺=260.1.

Step 4: 1-(cyclobutylmethyl)azetidine-3-carboxylic acid: to a solutionof benzyl 1-(cyclobutylmethyl)azetidine-3-carboxylate (650 mg, 2.51mmol, 1.00 eq.) in methanol (10 mL) was added Palladium on carbon (65mg) and the solution was degassed and back filled with hydrogen. Theresulting solution was stirred for 2 hours at room temperature. Thesolids were filtered out and concentrated under vacuum to afford 425 mg(99%) of 1-(cyclobutylmethyl)azetidine-3-carboxylic acid as a whitesolid; LC-MS (ES, m/z): [M+H]⁺=170.1.

Step 5:3-phenyl-N-[trans-3-([[1-(cyclobutylmethyl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamide:a solution of3-phenyl-N-[trans-3-(hydrazinecarbonyl)cyclobutyl]-isoxazole-5-carboxamide(300 mg, 1.00 mmol, 1.00 eq.),1-(cyclobutylmethyl)azetidine-3-carboxylic acid (200 mg, 1.20 mmol, 1.20eq.), T₃P (3.18 g, 5.00 mmol, 5.00 eq., 50%) and TEA (505 mg, 4.99 mmol,5.00 eq.) in tetrahydrofuran (10 mL) was stirred for 30 min at roomtemperature. The reaction was then quenched by the addition of water,extracted with ethyl acetate and the aqueous layers combined andconcentrated under vacuum. The crude product was purified byFlash-Prep-HPLC with the following conditions (IntelFlash-1): Column,C18; mobile phase, MeCN/H₂O=5:95 increasing to MeCN/H₂O=95:5 within 30min; Detector, UV 254 nm to afford 210 mg (47%) of3-phenyl-N-[trans-3-([[1-(cyclobutylmethyl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamideas a light yellow solid; LC-MS (ES, m/z): [M+H]⁺=452.1.

Step 6:3-phenyl-N-[trans-3-[5-[1-(cyclobutylmethyl)azetidin-3-yl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamide:I₂ (401 mg, 1.58 mmol, 2.50 eq.), TEA (415 mg, 4.10 mmol, 6.50 eq.) and3-phenyl-N-[trans-3-([[1-(cyclobutylmethyl)azetidin-3-yl]formohydrazido]carbonyl)cyclobutyl]-isoxazole-5-carboxamide(285 mg, 0.63 mmol, 1.00 eq.) were added to a solution of Ph₃P (414 mg,1.58 mmol, 2.50 eq.) in dichloromethane (20 mL) under N₂. The reactionmixture was stirred for 1 hour at room temperature, quenched with waterand then extracted with ethyl acetate and the organic layers combined.The organic layer was washed with brine, dried over anhydrous sodiumsulfate and concentrated under vacuum. The residue was applied onto asilica gel column with DCM/MeOH (25:1). The resulting crude product waspurified by Prep-HPLC with the following conditions (HPLC-10): Column, XBridge Prep C18 OBD Column, 19*150mm, 5 um; mobile phase, water (0.05%NH₄HCO₃) and ACN (30% ACN up to 80% within 8 min); Detector, UV 254 nmto give 125.6 mg (46%) of3-phenyl-N-[trans-3-[5-[1-(cyclobutylmethyl)azetidin-3-yl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=434.3; ¹H NMR (400 MHz,DMSO-d₆, ppm): δ 9.45-9.43 (d, 1H, J=7.6 Hz), 7.95-7.93 (m, 2H), 7.65(s, 1H), 7.55-7.54 (m, 2H), 4.71-4.63 (m, 1H), 3.88-3.81 (m, 1H),3.74-3.67 (m, 1H), 3.59-3.55 (t, 2H, J=7.2 Hz), 3.31 (s, 1H), 3.29-3.26(d, 1H, J=6.8 Hz), 2.70-2.63 (m, 4H), 2.45-2.43 (m, 2H), 2.32-2.24 (m,1H), 1.99-1.95 (m, 2H), 1.88-1.73 (m, 2H), 1.67-1.59 (m, 2H); HPLCpurity: 99.3% at 254 nm.

Examples 28 and 29N-(cis-3-(5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-(cis-3-(4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: 1-[cis-3-aminocyclobutyl]-1H-1,2,3-triazol-5-yl]methanolhydrochloride: a solution of tert-butylN-[cis-3-[4/5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]carbamate(prepared using a procedure similar to example 36; 400 mg, 1.49 mmol,1.00 eq.) in hydrogen chloride/MeOH (5 mL) was stirred for 18 hours atroom temperature. The resulting mixture was concentrated under vacuumand diluted with 3 mL of dioxane. The solids were collected byfiltration and dried in an oven under reduced pressure to give 301 mg(crude) of 1-[cis-3-aminocyclobutyl]-1H-1,2,3-triazol-5-yl]methanolhydrochloride as a white solid; LC-MS (ES, m/z): [M+H]⁺=167.1.

Step 2:3-phenyl-N-[cis-3-[4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamideand3-phenyl-N-[cis-3-[5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamide:DIEA (787 mg, 6.09 mmol, 3.00 eq.) was added dropwise to a cold solution(10° C.) of [1-[cis-3-aminocyclobutyl]-1H-1,2,3-triazol-4/5-yl]methanolhydrochloride (410 mg, 2.00 mmol, 1.00 eq.) in NMP (4 mL) and stirredfor 30 min at 25° C., followed by the addition of a solution of3-phenylisoxazole-5-carbonyl chloride (310 mg, 1.64 mmol, 1.00 eq.) inNMP (1 mL) dropwise with stirring at 0 to 10° C. The reaction wasstirred for 30 min and then quenched by the addition of 0.5 mL ofmethanol. The mixture was stirred at 25° C. for 30 min then 40 mL ofwater was added. The crude solid was collected by filtration andpurified by prep-HPLC: Column: XBridge BEH130 Prep C18 OBD Column 19*150mm, 5 um, 13 nm; Mobile Phase A: water (10 mmol/L NH₄HCO₃), Mobile PhaseB: ACN; Flow rate: 20 mL/min; Gradient: 22% B to 47% B in 8 min; 254 nmto give 152 mg (22%) of3-phenyl-N-[cis-3-[5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid and 143.15 mg (28%) of3-phenyl-N-[cis-3-[4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid.

3-phenyl-N-[cis-3-[5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamide:LC-MS (ES, m/z): [M+1]⁺=340.0; ¹H NMR (300 MHz, DMSO-d₆, ppm): δ9.48-9.45 (d, J=7.5 Hz, 1H), 7.94-7.91 (m, 2H), 7.66-7.62 (m, 2H),7.56-7.54 (m, 3H), 5.46-5.42 (m, 1H), 4.89-4.80 (m, 1H), 4.58-4.57 (d,J=5.4 Hz, 2H), 4.45-4.35 (m, 1H), 2.92-2.80 (m, 4H); HPLC purity: 99.2%at 254 nm.

3-phenyl-N-[cis-3-[4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamide:LC-MS (ES, m/z): [M+1]⁺=340.0; ¹H NMR (300 MHz, DMSO-d₆, ppm): δ9.41-9.39 (d, J=8.4 Hz, 1H), 8.16 (s, 1H), 7.96-7.93 (m, 2H), 7.67 (s,1H), 7.56-7.54 (m, 3H), 5.23-5.19 (t, J=5.6 Hz, 1H), 4.98-4.92 (m, 1H),4.55-4.53 (d, J=5.4 Hz, 2H), 4.45-4.37 (m, 1H), 2.98-2.90 (m, 2H),2.75-2.65 (m, 2H); HPLC purity: 99.3% at 254 nm.

Examples 30 and 31N-(trans-3-(5-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-5-phenylisoxazole-3-carboxamideandN-(trans-3-(4-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-5-phenylisoxazole-3-carboxamide

Step 1: oxetane-3-carbaldehyde: a solution of oxetan-3-ylmethanol (2 g,22.70 mmol, 1.00 eq.) in dichloromethane (20 mL) and1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (11.7 g, 27.59mmol, 1.00 eq.) was stirred for 2 hours at 25° C. The solids werefiltered out and the mixture was concentrated under vacuum to give 2.1 g(crude) of oxetane-3-carbaldehyde as yellow oil.

Step 2: 3-ethynyloxetane: a solution of oxetane-3-carbaldehyde (2.1 g,24.39 mmol, 1.00 eq.), potassium carbonate (6.6 g, 47.75 mmol, 2.00 eq.)and dimethyl (1-diazo-2-oxopropyl)phosphonate (7 g, 36.44 mmol, 1.50eq.) in methanol (30 mL) was stirred for 3 hours at 25° C. The resultingsolution was diluted with 150 mL of water, extracted with ethyl acetate(2×100 mL) and the organic layers combined. The resulting mixture waswashed with brine (2×100 mL), dried over anhydrous sodium sulfate andconcentrated under vacuum to give 820 mg (41%) of 3-ethynyloxetane ascolorless oil.

Step 3: trans-3-azidocyclobutan-1-amine: a solution of tert-butylN-[trans-3-azidocyclobutyl]carbamate (1 g, 4.71 mmol, 1.00 eq.) intetrahydrofuran (20 mL)/conc. HCl aqueous (5 mL) was stirred for 2 hoursat 25° C. The resulting mixture was concentrated under vacuum to give800 mg (crude) of cis-3-azidocyclobutan-1-amine as yellow oil.

Step 4: 3-phenyl-N-[trans-3-azidocyclobutyl]-isoxazole-5-carboxamide:HATU (1.37 g, 3.60 mmol, 1.50 eq.), DIEA (928 mg, 7.18 mmol, 3.00 eq.)and 3-phenyl-isoxazole-5-carboxylic acid (453 mg, 2.39 mmol, 1.00 eq.)were added to a solution of trans-3-azidocyclobutan-1-amine (800 mg,7.13 mmol, 1.00 eq.) in dichloromethane (15 mL) and the mixture wasstirred for 2 hours at 25° C. The resulting solution was diluted with150 mL of H₂O, extracted with ethyl acetate (2×100 mL) and the organiclayers combined. The organic layer was washed with brine (2×100 mL),dried over anhydrous sodium sulfate and concentrated under vacuum. Theresidue was applied onto a silica gel column with petroleum ether:ethylacetate (10:1) to afford 390 mg (19%) of3-phenyl-N-[trans-3-azidocyclobutyl]-isoxazole-5-carboxamide as a yellowsolid; LC-MS (ES, m/z): [M+H]⁺=284.1.

Step 5:5-phenyl-N-[trans-3-[4-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-3-carboxamideand5-phenyl-N-[trans-3-[5-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-3-carboxamide:a solution of3-phenyl-N-[(trans-3-azidocyclobutyl]isoxazole-5-carboxamide (283 mg,1.00 mmol, 1.00 eq.) and 3-ethynyloxetane (410 mg, 4.99 mmol, 5.00 eq.)in DMF (10 mL) was stirred for 16 hours at 100° C. The resultingsolution was diluted with 100 mL of H₂O, extracted with ethyl acetate(2×100 mL) and the combined organic layers were dried over anhydroussodium sulfate and concentrated under vacuum. The crude product waspurified by Prep-TLC (petroleum ether:ethyl acetate=1:5). The resultingisomers was separated by Chiral-Prep-HPLC with the following conditions(Prep-HPLC-032): Column, Phenomenex Lux 5 u Cellulose-4 AXIA Packed,250*21.2 mm, 5 um; mobile phase, Hex and ethanol (hold 50.0% ethanol in20 min); Detector, UV 254/220 nm to afford 16.8 mg (5%) of5-phenyl-N-[trans-3-[5-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-3-carboxamideas a white solid and 29.1 mg (8%) of3-phenyl-N-[trans-3-[4-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamideas a white solid.

5-phenyl-N-[trans-3-[5-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-3-carboxamide:LC-MS (ES, m/z): [M+H]⁺=366.1; ¹H NMR (300 MHz, DMSO-d₆) δ 9.51-9.49 (d,J=7.2 Hz, 1H), 7.96-7.94 (m, 3H), 7.68 (s, 1H), 7.57-7.56 (m, 3H),4.97-4.93 (m, 3H), 4.75-4.70 (m, 1H), 4.66-4.62 (m, 2H), 4.48-4.42 (m,1H), 2.86-2.74 (m, 4H); HPLC purity: 99.5% at 254 nm.

5-phenyl-N-[trans-3-[4-(oxetan-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-3-carboxamide:LC-MS (ES, m/z): [M+H]⁺=366.1; ¹H NMR (300 MHz, DMSO-d₆) δ 9.52-9.50 (d,J=6.9 Hz, 1H), 8.33 (s, 1H), 7.96-7.93 (m, 2H), 7.68 (s, 1H), 7.56-7.54(m, 3H), 5.34-5.24 (m, 1H), 4.92-4.88 (m, 2H), 4.76-4.65 (m, 3H),4.42-4.32 (m, 1H), 2.91-2.75 (m, 4H); HPLC purity: 98% at 254 nm.

Example 32 and 33N-(trans-3-(4-(1-methylazetidin-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-(trans-3-(5-(1-methylazetidin-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: tert-butyl 3-formylazetidine-1-carboxylate: a solution oftert-butyl 3-(hydroxymethyl)azetidine-1-carboxylate (3.74 g, 19.97 mmol,1.00 equip), and Dess-Martin reagent (12.72 g, 30.00 mmol, 1.50 eq.) indichloromethane (100 mL) was stirred for 2 hours at room temperature.The solids were filtered out, the resulting mixture was concentratedunder vacuum to give 3.8 g (crude) of tert-butyl3-formylazetidine-1-carboxylate as a white solid.

Step 2: tert-butyl 3-ethynylazetidine-1-carboxylate: a solution oftert-butyl 3-formylazetidine-1-carboxylate (3.7 g, 19.98 mmol, 1.00eq.), potassium carbonate (8.28 g, 59.91 mmol, 3.00 eq.) and dimethyl(1-diazo-2-oxopropyl)phosphonate (5.76 g, 29.98 mmol, 1.50 eq.) inmethanol (50 mL) was stirred for 3 hours at room temperature. Theresulting solution was diluted with 200 mL of ether, washed withsaturated sodium bicarbonate aqueous (2×200 mL), dried over anhydroussodium sulfate and concentrated under vacuum to give 3.282 g (crude) oftert-butyl 3-ethynylazetidine-1-carboxylate as yellow oil.

Step 3: tert-butyl3-[1-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1H-1,2,3-triazol-4/5-yl]azetidine-1-carboxylate:a solution of3-phenyl-N-[trans-3-azidocyclobutyl]isoxazole-5-carboxamide (327 mg,1.15 mmol, 1.00 eq.) and tert-butyl 3-ethynylazetidine-1-carboxylate(627 mg, 3.46 mmol, 3.00 eq.) in DMF (4 mL) was placed in a microwavereactor for 6 hours at 140° C. The resulting mixture was concentratedunder vacuum and the residue was applied onto a silica gel column withethyl acetate/petroleum ether (1:1) to give 553 mg (crude) mixture oftert-butyl3-[1-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1H-1,2,3-triazol-5-yl]azetidine-1-carboxylateand tert-butyl3-[1-[trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1H-1,2,3-triazol-4-yl]azetidine-1-carboxylateas a yellow solid; LC-MS (ES, m/z): [M+H]⁺=465.3.

Step 4:3-phenyl-N-[trans-3-[4/5-(azetidin-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamidehydrochloride: a solution of the mixture of tert-butyl3-[1-trans-3-(3-phenylisoxazole-5-amido)cyclobutyl]-1H-1,2,3-triazol-4/5-yl]azetidine-1-carboxylate(553 mg, 1.19 mmol, 1.00 eq.) in tetrahydrofuran (10 mL)/hydrogenchloride aqueous (6N, 6 mL) was stirred for 2 hours at room temperature.The resulting mixture was concentrated under vacuum to give 551 mg(crude) of a mixture of3-phenyl-N-[trans-3-[4/5-(azetidin-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamidehydrochloride as a brown solid; LC-MS (ES, m/z): [M−HCl+H]⁺=365.3.

Step 5:N-(trans-3-(4-(1-methylazetidin-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-(trans-3-(5-(1-methylazetidin-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:a solution of the mixture of3-phenyl-N-[trans-3-[4/5-(azetidin-3-yl)-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamidehydrochloride, POM (302 mg, 6.86 mmol, 4.99 eq.) and acetic acid (165mg, 2.75 mmol, 2.00 eq.) in DCM (20 mL) was stirred for 30 min at roomtemperature. NaBHCN (346 mg, 5.49 mmol, 4.00 eq.) was added to thereaction mixture and it was stirred for 3 hours at room temperature. Themixture was concentrated under vacuum and the crude product was purifiedby Prep-HPLC with the following conditions (HPLC-10): Column, XBridgeC18 OBD Prep Column, 19 mm×250 mm; mobile phase, water (10 mmol/LNH₄HCO₃) and ACN (40.0% ACN up to 90.0% in 8 min); Detector, UV 254/220nm. This resulted in 50 mg crude first peak, 20 mg (4%) of second peakas a white solid and 75 mg (15%) of third peak) as a white solid. Thenthe crude first peak was purified by Prep-HPLC with the followingconditions (HPLC-10): Column, XBridge C18 OBD Prep Column, 19 mm×250 mm;mobile phase, water (0.05% TFA) and ACN (20.0% ACN up to 50.0% in 10min); Detector, UV 254/220 nm to give 30 mg of product as a yellow oil.

First peak (putative structure):

Second peak (putative structure): LC-MS (ES, m/z): [M+H]⁺=379.2; ¹H NMR(400 MHz, CD₃OD, ppm): 8.05(s, 1H), 7.89-7.88 (d, J=2.8 Hz, 2H),7.52-7.51 (m, 3H), 7.43 (s, 1H), 5.11 (br, 1H), 4.90-4.88 (m, 1H),4.74-7.54 (m, 1H), 4.54-4.46 (m, 2H), 4.36-4.25 (m, 2H), 3.10-2.91 (m,5H), 2.89-2.88 (m, 2H); HPLC purity: 99.4% at 254 nm.

Third peak:N-(trans-3-(4-(1-methylazetidin-3-yl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:LC-MS [M+H]⁺=379.3; ¹H NMR (400 MHz, DMSO-d₆, ppm): δ 9.53-9.51 (d,J=6.8 Hz, 1H), 8.23 (s, 1H), 7.96-7.74 (m, 2H), 7.69 (s, 1H), 7.56-7.54(m, 3H), 5.28-5.24 (m, 1H), 4.72-4.67 (m, 1H), 3.64-3.56 (m, 3H),3.12-3.09 (m, 2H), 2.88-2.75 (m, 4H), 2.08 (s, 3H); HPLC purity; 98.7%at 254 nm.

Examples 34N-(trans-3-(5-(1-(methylsulfonyl)ethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Preparation of intermediates A and B

Step 1: N-[trans-3-[4/5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]carbamate:a solution of tert-butyl N-[trans-3-azidocyclobutyl]carbamate (2 g, 9.42mmol, 1.00 eq.) and (2R)-but-3-yn-2-ol (3.3 g, 47.08 mmol, 5.00 eq.) inDMF (5 mL) was stirred for overnight at 100° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (3:1) togive 2.1 g (79%) of a mixture of tert-butylN-[trans-3-[4/5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]carbamateas a light yellow solid; LC-MS (ES, m/z): [M+H]⁺=283.2.

Step 2:(1R)-1-[1-[trans-3-aminocyclobutyl]-1H-1,2,3-triazol-4/5-yl]ethanol: asolution of the mixture of tert-butylN-[trans-3-1-[4/5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]carbamatein dioxane (10 mL)/hydrogen chloride aqueous (6N, 3 mL) was stirred for2 hours at room temperature. The resulting mixture was concentratedunder vacuum to give 1.45 g (crude) of a mixture of(1R)-1-[1-[trans-3-aminocyclobutyl]-1H-1,2,3-triazol-4/5-yl]ethanol as alight yellow solid; LC-MS-PH (ES, m/z): [M+H]⁺=183.1.

Step 3:N-(trans-3-(5-((R)-1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide(A) andN-(trans-3-(4((R)-1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide(B): DIEA (2.55 g, 3.00 eq.) and 3-phenylisoxazole-5-carbonyl chloride(1.77 g, 8.53 mmol, 1.30 eq.) were added dropwise to a cold (0° C.)solution of a mixture of(1R)-1-[1-[trans-3-aminocyclobutyl]-1H-1,2,3-triazol-4/5-yl]ethanol indichloromethane (20 mL) and the mixture was stirred for 2 hours at 0° C.The resulting mixture was washed with hydrogen chloride aqueous (2N)(1×50 mL) and potassium carbonate (5%) (1×100 mL), concentrated undervacuum, and the crude product was purified by prep-HPLC to give 0.236 g(10%) ofN-(trans-3-(5-((R)-1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideand 0.333 g (14%) ofN-(trans-3-(4-((R)-1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=354.2.

Preparation ofN-(trans-3-(5-(1-(methylsulfonyl)ethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 4: N-(trans-3-(5-((R)-1-chloroethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:MsCl (81.3 mg, 2.00 eq.) was added dropwise to a 0° C. solution of3-phenyl-N-[(trans-3-[5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamide(126 mg, 0.36 mmol, 1.00 eq.) and TEA (108 mg, 3.00 eq.) indichloromethane (20 mL) and the solution was stirred for 5 hours at roomtemperature. The mixture was diluted with 30 ml of dichloromethane,washed with CuSO₄ aqueous (2×30 mL) and concentrated under vacuum togive 151 mg (crude) ofN-(trans-3-(5((R)-1-chloroethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a brown oil; LC-MS (ES, m/z): [M+H]⁺=372.1.

Step 5: a solution ofN-(trans-3-(5((R)-1-chloroethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide(151 mg, 0.41 mmol, 1.00 eq.) and NaSMe (50 mg, 2.00 eq.) in DMF (5 mL)was stirred for 5 hours at 100° C. in an oil bath. The reaction was thenquenched by the addition of 20 mL of water, extracted with ethyl acetate(3×20 mL) and the organic layers combined. The resulting mixture waswashed with brine (2×10 mL) and concentrated under vacuum to give 189 mg(crude) of3-phenyl-N-[trans-3-[5-[1-(methylsulfanyl)ethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-isoxazole-5-carboxamideas brown oil; LC-MS (ES, m/z): [M+H]⁺=384.4.

Step 6: mCPBA (338 mg, 1.96 mmol, 4.00 eq.) was added in several batchesto a 0° C. solution of3-phenyl-N-[trans-3-[5-[1-(methylsulfanyl)ethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]isoxazole-5-carboxamide(189 mg, 0.49 mmol, 1.00 eq.) in dichloromethane (10 mL) and the mixturewas stirred for 5 hours at room temperature. The reaction mixture wasdiluted with 50 mL of dichloromethane, washed with Na₂S₂O₃ aqueous (1×50mL) and concentrated under vacuum. The crude product was purified byPrep-HPLC with the following conditions (Water): Column, Xbridge PrepC18, 5 um,19*150 mm; mobile phase, water with 0.08% NH₄HCO₃ and CH₃CN(30% CH₃CN up to 70% CH₃CN in 10 min, up to 95% in 2 min and down to 30%in 2 min); Detector, UV 254 nm and 220 nm to give 23.3 mg (11%) of3-phenyl-N-[trans-3-[5-[1-methanesulfonylethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-isoxzzole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=416.2; ¹H NMR (DMSO-d₆, 400MHz): δ 9.52-9.49 (d, J=12.0 Hz, 1H), 7.95-7.93 (m, 3H), 7.69 (s, 1H),7.56-7.54 (m, 3H), 5.36-5.29 (m, 1H), 4.93-4.87 (m, 1H), 4.85-4.76 (m,1H), 3.01 (s, 3H), 2.92-2.78 (m, 4H), 1.69-1.67 (d, J=7.2 Hz, 3H); HPLCpurity: 99.2% at 254 nm.

Example 35N-(trans-3-(4-(1-(methylsulfonyl)ethyl)-1H-1,2,3-triazol-1-yl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

The title compound was prepared by a similar procedure as shown inexample 34 using intermediate B as the starting material. The crudeproduct was purified by Prep-HPLC with the following conditions (Water):Column, Xbridge Prep C18, 5 um,19*150 mm; mobile phase, water with 0.08%NH₄HCO₃ and CH₃CN (30% CH₃CN up to 75% CH₃CN in 10 min, up to 95% in 2min and down to 30% in 2 min); Detector, UV 254 nm and 220 nm to give54.5 mg (17.6%) of3-phenyl-N-[trans-3-[5-[1-methanesulfonylethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-isoxazole-5-carboxamideas a white solid; LC-MS (ES, m/z): [M+H]⁺=416.2; ¹H NMR (DMSO-d₆, 400MHz): δ 9.54-9.52 (d, J=7.2 Hz, 1H), 8.43 (s, 1H), 7.96-7.94 (m, 2H),7.68 (s, 1H), 7.56-7.54 (m, 3H), 5.37-5.29 (m, 1H), 4.72-4.68 (m, 2H),2.95 (s, 3H), 2.88-2.81 (m, 4H), 1.68-1.66 (d, J=7.2 Hz, 3H); HPLCpurity: 98.4% at 254 nm.

Example 363-(4-fluorophenyl)-N-(trans-3-(5-((R)-1-hydroxyethyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)isoxazole-5-carboxamide

The title compound was prepared using a methodology similar to the oneshown in example 13 and purified by Flash-Prep-HPLC with the followingconditions (IntelFlash-1): Column, C18; mobile phase, H₂O/CH₃CN=100:1increasing to H₂O/CH₃CN=1:100 within 30 min; Detector, UV 254 nm to give37.7 mg (25%) as a white solid; LC-MS (ES, m/z): [M+1]⁺=373.0; ¹H NMR(400 MHz, DMSO-d₆): δ 9.49-9.47 (d, J=7.6 Hz, 1H), 8.03-7.98 (m, 2H),7.68 (s, 1H), 7.42-7.37 (m, 2H), 5.97-5.95 (d, J=6 Hz, 1H), 7.96-4.89(m, 1H), 4.71-4.65 (m, 1H), 3.76-3.72 (m, 1H), 2.73-2.60 (m, 4H),1.50-1.48 (d, J=6.4 Hz, 3H); HPLC purity: 99.8% at 254 nm.

Examples 37 and 38N-((1S,3s)-3-((5-((R)-1-hydroxyethyl)-1,3,4-oxadiazol-2-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-((1R,3r)-3-((5-((R)-1-hydroxyethyl)-1,3,4-oxadiazol-2-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1: Ethyl 2-(3-((tert-Butoxycarbonyl)amino)cyclobutylidene)acetate.To a 250-mL round-bottom flask was placed a solution of tert-butylN-(3-oxocyclobutyl)carbamate (13 g, 70.19 mmol, 1.00 equiv) in toluene(100 mL), then (carbethoxymethylene)triphenylphosphorane (CEMTPP) (25.7g, 73.77 mmol, 1.05 equiv) was added. The resulting solution was stirredfor 2 h at 100° C. The resulting mixture was concentrated under vacuumthen the residue was applied onto a silica gel column and eluted withEtOAc/petroleum ether (1:5) affording 16.7 g (93%) of ethyl2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutylidene) acetate as a whitesolid. LCMS (ES, m/z): [M+H]⁺=256.2.

Step 2: Ethyl 2-(3-((tert-Butoxycarbonyl)amino)cyclobutyl)acetate. To a250-mL round-bottom flask, was placed a solution of ethyl2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutylidene)acetate (16.7 g,65.41 mmol, 1.00 equiv, as prepared above) in MeOH (100 mL), then Pd oncarbon (1 g) was added. The solution was degassed and back filled withhydrogen. The resulting solution was stirred for 3 h at RT. The solidswere removed by filtration, then the resulting solution was concentratedunder reduced pressure affording 15.5 g (92%) of ethyl2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutyl) acetate as colorless oil.LCMS (ES, m/z): [M+H]⁺=258.2.

Step 3: 2-(3-[[(tert-Butoxy)carbonyl]amino]cyclobutyl)acetic acid. To a500-mL round-bottom flask was placed a solution of ethyl2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutyl)acetate (15.5 g, 60.23mmol, 1.00 equiv) in THF/H₂O (150/50 mL) and LiOH (2.16 g, 90.20 mmol,1.50 equiv). The resulting solution was stirred for 3 h at rt, then theresulting mixture was concentrated under reduced pressure. The resultingsolution was diluted with 200 mL of aq.NaHSO₄, extracted with 3×150 mLof EtOAc, and then the organic extracts were combined. The solution waswashed with 2×100 mL of brine, dried, and concentrated under reducedpressure, affording 13.8 g (crude) of2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutyl)acetic acid as colorlessoil. LCMS (ES, m/z): [M+H]⁺=230.1.

Step 4: tert-ButylN-(3-[2-[(2R)-2-[(tert-Butyldimethylsilyl)oxy]propanehydrazido]-2-oxoethyl]cyclobutyl)carbamate.To a 500-mL round-bottom flask was placed a solution of2-(3-[[(tert-butoxy)carbonyl]amino]cyclobutyl)acetic acid (13 g, 56.70mmol, 1.00 equiv) in THF (250 mL). To this solution were added(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazide (18.6 g, 85.18mmol, 1.50 equiv), TEA (28.9 g, 285.60 mmol, 5.00 equiv) and T₃P (72 g,113.21 mmol, 2.00 equiv). The reaction was stirred for 2 h at RT, thendiluted with 400 mL of H₂O and extracted with EtOAc (3×300 mL). Theorganic extracts were combined, washed with brine (2×300 mL), dried overNa₂SO₄, and concentrated under reduced pressure. The residue was appliedonto a silica gel column with petroleum ether/EtOAc (2:1) affording 14.5g (60%) of tert-butylN-(3-[2-[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazido]-2-oxoethyl]cyclobutyl)carbamateas yellow oil. LCMS (ES, m/z):[M+H]⁺=430.3.

Step 5: tert-butylN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]carbamate.To a 250-mL 3-necked round-bottom flask purged and maintained withnitrogen was placed a solution of PPh₃ (2.84 g, 10.83 mmol, 2.00 equiv)in DCM (100 mL). To this solution were added I₂ (2.75 g, 10.83 mmol,2.00 equiv), TEA (3.7 g, 36.56 mmol, 5.00 equiv) and tert-butylN-[3-([N-[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanoyl]hydrazinecarbonyl]methyl)cyclobutyl]carbamate(3.1 g, 7.22 mmol, 1.00 equiv). The resulting solution was stirred for 2h at RT, then diluted with 150 mL of H₂O and extracted with EtOAc (2×150mL). The organic extracts were combined, washed with brine (2×100 mL),dried over anhydrous Na₂SO₄, and concentrated under reduced pressure.The residue was applied onto a silica gel column and eluted withpetroleum ether/EtOAc (5:1) affording 2 g (67%) of tert-butylN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]carbamateas yellow oil. LCMS (ES, m/z): [M+H]⁺=412.3. ¹H NMR (400 MHz, CDCl3): δ5.11-5.02 (m, 1H), 4.15-4.08 (m, 1H), 3.02-2.92 (m, 2H), 2.59-2.52 (m,1H), 2.26-2.19 (m, 1H), 2.14-2.08 (m, 1H), 1.70-1.62 (m, 2H), 1.58-1.56(d, J=7.6 Hz, 2H), 1.43 (s, 9H), 0.88 (s, 9H), 0.11 (s, 3H), 0.04 (s,3H).

Step 6:3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutan-1-amine.To a 100-mL round-bottom flask was placed a solution of tert-butylN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]carbamate(2 g, 4.86 mmol, 1.00 equiv) in DCM (50 mL), then TFA (3 mL, 8.00 equiv)was added. The resulting solution was stirred for 2 h at RT thenconcentrated under reduced pressure affording 2.5 g (crude) of3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutan-1-amineas yellow crude oil. LCMS (ES, m/z): [M+H]⁺=312.2.

Step 7:N-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide.To a 100-mL round-bottom flask was placed a solution of3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutan-1-amine(1 g, crude) in DCM (50 mL), then 3-phenyl-1,2-oxazole-5-carboxylic acid(468 mg, 2.47 mmol, 1.00 equiv), HATU (1.28 g, 3.37 mmol, 1.20 equiv)and DIEA (1.1 mL, 2.80 equiv) were added. The resulting solution wasstirred for 2 h at RT, washed with water (3×50 mL), and thenconcentrated under reduced pressure affording 680 mg (crude) ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamideas yellow oil. LCMS (ES, m/z): [M+H]⁺=483.2.

Step 8:N-[3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask was placed a solution ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide(1 g, 2.07 mmol, 1.00 equiv) in THF (20 mL), then Py.HF (2.5 mL, 8.00equiv) was added. The resulting solution was stirred for 2 h at 0° C.then quenched by the addition of 100 mL of brine. The resulting mixturewas extracted with EtOAc (3×100 mL), then the organic extracts werecombined, washed with NaHCO₃ (2×100 mL), brine (2x 100 mL), andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with petroleum ether/EtOAc (1:3) affording460 mg ofN-[3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamideas light yellow oil. LCMS (ES, m/z): [M+H]⁺=369.2.

N-[3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide(520 mg, 1.41 mmol, 1.00 equiv) was purified by Prep-SFC with thefollowing conditions: Column: Phenomenex Lux 5 u Cellulose-4, 250*50 mm;Mobile Phase A:CO₂:50, Mobile Phase B: MeOH-Preparative:50; Flow rate:150 mL/min; 220 nm; RT1:6.38; RT2:7.33 affording 98.6 mg (19%) of3-phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 78.7 mg (15%) of3-phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=369.0. ¹H NMR (300 MHz, DMSO-d₆): δ 9.23-9.20 (d,J=7.8 Hz, 1H), 7.94-7.91 (m, 2H), 7.62 (s, 1H), 7.55-7.53 (m, 3H), 5.92(s, 1H), 4.92-4.85 (q, J=6.6 Hz, 1H), 4.35-4.27 (m, 1H), 2.99-2.97 (d,J=6.6 Hz, 2H), 2.45-2.35 (m, 3H), 1.98-1.92 (m, 2H), 1.47-1.44 (d, J=6.6Hz, 3H). Purity (HPLC, 254 nm): 99.0%.

3-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=369.0. ¹H NMR (300 MHz, DMSO-d₆): δ 9.23-9.20 (d,J=8.4 Hz, 1H), 7.94-7.91 (m, 2H), 7.62 (s, 1H), 7.55-7.53 (m, 3H), 5.92(s, 1H), 4.92-4.85 (q, J=6.6 Hz, 1H), 4.35-4.28 (m, 1H), 2.99-2.97 (d,J=6.6 Hz, 2H), 2.45-2.35 (m, 3H), 1.98-1.92 (m, 2H), 1.47-1.44 (d, J=6.6Hz, 3H). Purity (HPLC, 254 nm): 98.3%.

Example 39 and 403-(4-Fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand 3-(4-Fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

The title compounds were prepared using a methodology similar to the oneshown in Example 37. The mixture was separated by Chiral-Prep-HPLC withthe following conditions: Column: Repaired IA, 21.2*150 mm, 5 um; MobilePhase A:Hex-HPLC, Mobile Phase B: EtOH-HPLC; Flow rate: 20 ml/min;Gradient: 50 B to 50 B in 11.5 min; 254/220 nm; RT1:7.21; RT2:8.75. Thisresulted in 95 mg (34%) of3-(4-fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 79.6 mg (28%) of3-(4-fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-(4-fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=386.9. 1H NMR (300 MHz, DMSO-d₆): δ 9.23-9.20 (d,J=7.8 Hz, 1H), 8.02-7.97 (m, 2H), 7.63 (s, 1H), 7.42-7.36 (m, 2H),5.92-5.90 (d, J=5.4 Hz 1H), 4.91-4.87 (m, 1H), 4.35-4.28 (m, 1H),2.99-2.97 (d, J=6.9 Hz, 2H), 2.45-2.40 (m, 3H), 1.97-1.92 (m, 2H),1.47-1.44 (d, J=6.9 Hz, 3H). Purity (HPLC, 254 nm): 99.3%.

3-(4-fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=386. ¹H NMR (300 MHz, DMSO-d₆): δ 9.31-9.29 (d,J=7.2 Hz, 1H), 8.01-7.96 (m, 2H), 7.64 (s, 1H), 7.41-7.35 (m, 2H),5.92-5.90 (d, J=5.7 Hz 1H), 4.93-4.84 (m, 1H), 4.58-4.51 (q, J=7.5 Hz,1H), 3.10-3.07 (d, J=7.8 Hz, 2H), 2.70-2.64 (s, 1H), 2.38-2.29 (m, 2H),2.18-2.09 (m, 2H), 1.46-1.44 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm):98.0%.

Examples 41 and 423-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: tert-ButylN-[3-([5-[(1R)-1-[(tert-Butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]carbamate.To a 250-mL round-bottom flask was placed a solution of tert-butylN-(3-[2-[(2R)-2-[(tert-butyldimethylsilyl)oxy]propanehydrazido]-2-oxoethyl]cyclobutyl)carbamate(6 g, 13.97 mmol, 1.00 equiv) in toluene (100 mL) then Lawesson'sreagent (8.5 g, 21.02 mmol, 1.50 equiv) was added. The resultingsolution was stirred for 1.5 h at 80° C. then concentrated under reducedpressure. The resulting solution was diluted with 200 mL of H₂O and thenextracted with EtOAc (3×200 mL). The organic extracts were combined,washed with brine (2×200 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The crude product was purified byFlash-Prep-HPLC (CombiFlash-1: Column, C18; mobile phase, X:H₂O (0.5%NH₄HCO₃), Y:CAN, X/Y=80/20 increasing to X/Y=5/95 within 40 min;Detector, UV 254 nm) affording 2.2 g (37%) of tert-butylN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]carbamateas yellow oil. LCMS (ES, m/z): [M+H−BOC]⁺=328.0.

Step 2:3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutan-1-amine.To a 50-mL round-bottom flask was placed a solution of tert-butylN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]carbamate(2.2 g, 5.14 mmol, 1.00 equiv) in DCM (20 mL) and TFA (4 mL). Theresulting solution was stirred for 1 h at RT then concentrated underreduced pressure affording 3 g (crude) of3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutan-1-amineas yellow oil.

Step 3:N-[3-([5-[(1R)-1-[(tert-butyldimethylsily)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutan-1-amine(500 mg, 1.53 mmol, 1.00 equiv) in DCM (20 mL), then HATU (753 mg, 1.98mmol, 1.30 equiv), 3-phenyl-1,2-oxazole-5-carboxylic acid (317 mg, 1.68mmol, 1.10 equiv) and DIEA (589 mg, 4.56 mmol, 3.00 equiv) were added.The resulting mixture was stirred for 2 h at RT then diluted with 100 mLof H₂O and extracted with EtOAc (2×50 mL). The organic extracts werecombined, washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:5) affording320 mg (42%) ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamideas yellow oil. LCMS (ES, m/z): [M+H]⁺=499.1.

Step 4:3-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 10-mL round-bottom flask was placed a solution ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-3-phenyl-1,2-oxazole-5-carboxamide(320 mg, 0.64 mmol, 1.00 equiv) in MeOH (3 mL), then Py.HF (1 mL) wasadded. The resulting solution was stirred for 2 h at rt, diluted with 50mL of H₂O, and extracted with EtOAc (2×50 mL). The organic extracts werecombined, washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:1). Theresulting isomers were separated by Chiral-Prep-HPLC (Prep-HPLC-004:Column, Phenomenex Lux 5 u Cellulose-4AXIA Packed, 250*21.2 mm, 5 um;mobile phase, Hex and IPA (hold 50.0% IPA in 18 min); Detector, UV254/220 nm) affording 88.7 mg (36%) of3-phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 57.8 mg (23%) of3-phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=385.0. ¹H NMR (300 MHz, DMSO-d₆) δ 9.23-9.20 (d,J=7.5 Hz, 1H), 7.94-7.91 (m, 2H), 7.62 (s, 1H), 7.55-7.53 (m, 3H),6.26-6.24 (d, J=5.1 Hz, 1H), 5.09-5.03 (m, 1H), 4.35-4.28 (m, 1H),3.19-3.16 (d, J=7.2 Hz, 2H), 2.43-2.34 (m, 3H), 1.98-1.92 (m, 2H),1.49-1.47 (d, J=6.3 Hz, 3H).). Purity (HPLC, 254 nm): 97.9%.

3-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=385. ¹H NMR (300 MHz, DMSO-d₆): δ 9.31-9.29 (d,J=7.2 Hz, 1H), 7.94-7.91 (m, 2H), 7.64 (s, 1H), 7.55-7.53 (m, 3H),6.25-6.24 (d, J=5.1 Hz, 1H), 5.09-5.01 (m, 1H), 4.60-4.52 (m, 1H),3.29-3.26 (m, 2H), 2.66-2.62 (m, 1H), 2.37-2.27 (m, 2H), 2.18-2.12 (m,2H), 1.49-1.47 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm): 98.4%.

Examples 43 and 443-(4-Fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-(4-Fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

The title compounds were prepared using a methodology similar to the oneshown in Example 41. The resulting isomers were separated by Prep-SFC(Prep SFC100: Column, Phenomenex Lux 5 u Cellulose-4AXIA Packed,250*21.2 mm, 5 um; mobile phase, CO2(60%), ETOH(0.2% DEA)-(40%);Detector, uv 220 nm) affording 125 mg (22%) of3-(4-fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 110.8 mg (20%) of3-(4-fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-(4-Fluorophenyl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=403. ¹H NMR (400 MHz, DMSO-d₆) δ 9.24-9.22 (d,J=8.0 Hz, 1H), 8.01-7.98 (m, 2H), 7.63 (s, 1H), 7.41-7.37 (m, 2H), 6.25(s, 1H), 5.05-5.04 (m, 1H), 4.34-4.28 (m, 1H), 3.18-3.16 (d, J=6.8 Hz,2H), 2.45-2.36 (m, 3H), 1.94-1.92 (m, 2H), 1.48-1.47 (d, J=6.4 Hz, 3H).Purity (HPLC, 254 nm): 99.4%.

3-(4-Fluorophenyl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-thiadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=403.0. ¹H NMR (300 MHz, DMSO-d₆) δ 9.32-9.29 (d,J=7.5 Hz, 1H), 8.02-7.97 (m, 2H), 7.65 (s, 1H), 7.42-7.36 (m, 2H),6.25-6.24 (d, J=5.1 Hz, 1H), 5.09-5.01 (m, 1H), 4.62-4.50 (m, 1H),3.29-3.26 (d, J=8.1 Hz, 2H), 2.69-2.60 (m, 1H), 2.37-2.27 (m, 2H),2.19-2.10 (m, 2H), 1.49-1.47 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm):96.3%.

Examples 45 and 46N-[(1s,3s)-3-([5-[(1R)-1-Hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamideandN-[(1r,3r)-3-([5-[(1R)-1-Hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide

Step 1: N-(thiophen-2-ylmethylidene)hydroxylamine. To a 100-mLround-bottom flask was placed a solution of thiophene-2-carbaldehyde (5g, 44.58 mmol, 1.00 equiv) in EtOH (50 mL) then NH₂OH.HCl (3.7 g, 1.20equiv) was added. The resulting solution was stirred for 2 h at RT thenthe reaction was extracted with EtOAc. The organic extracts werecombined, dried, and concentrated under reduced pressure affording 4.5 g(79%) of N-(thiophen-2-ylmethylidene)hydroxylamine as yellow oil. LCMS(ES, m/z): [M+H]⁺=128.0.

Step 2: Methyl 3-(Thiophen-2-yl)-1,2-oxazole-5-carboxylate. To a 100-mLround-bottom flask was placed a solution ofN-(thiophen-2-ylmethylidene)hydroxylamine (4.5 g, 35.39 mmol, 1.00equiv) in H₂O (50 mL), then methyl prop-2-ynoate (8 mL, 2.50 equiv), KCl(2.6 g, 1.00 equiv) and Oxone (14.4 g, 1.50 equiv) were added. Theresulting solution was stirred for 2 h at RT then the reaction wasextracted with EtOAc (3×100 mL). The organic extracts were combined,dried, and concentrated under reduced pressure affording 5.4 g (73%) ofmethyl 3-(thiophen-2-yl)-1,2-oxazole-5-carboxylate as a yellow solid.LCMS (ES, m/z): [M+H]⁺=210.0.

Step 3: 3-(thiophen-2-yl)-1,2-oxazole-5-carboxylic acid. To a 250-mLround-bottom flask was placed a solution of methyl3-(thiophen-2-yl)-1,2-oxazole-5-carboxylate (5.4 g, 25.81 mmol, 1.00equiv) in THF and H₂O (30 mL/10 mL), then LiOH (1.33 g, 55.53 mmol, 2.00equiv) was added. The resulting solution was stirred for 1 h at RT.After concentrating under reduced pressure, the residue was diluted with100 mL of H₂O then the resulting solution was washed with EtOAc (2×30mL). The pH value of the aqueous layer was adjusted to 3 with HCl, thenthe solution was extracted with EtOAc (3×100 mL). The organic extractswere combined, dried over anhydrous Na₂SO₄, and concentrated underreduced pressure affording 3.2 g (64%) of3-(thiophen-2-yl)-1,2-oxazole-5-carboxylic acid as a white solid. LCMS(ES, m/z):[M+H]⁺=196.1.

Step 4:N-[3-([5-[(1R)-1-[(tert-butyldimethylsily)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask was placed a solution of3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutan-1-amine(1.25 g, 4.02 mmol, 1.00 equiv) in DCM (30 mL) then3-(thiophen-2-yl)-1,2-oxazole-5-carboxylic acid (800 mg, 4.10 mmol, 1.02equiv), HATU (2.3 g, 6.05 mmol, 1.50 equiv) and DIEA (3.1 g, 24.01 mmol,6.00 equiv) were added. The resulting solution was stirred for 3 h at RTthen washed with brine (2×60 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:8 affording2.3 g (crude) ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamideas yellow oil. LCMS (ES, m/z): [M+H]⁺=489.2.

Step 5:N-[(1s,3s)-3-([5-[(1R)-1-Hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamideandN-[(1r,3r)-3-([5-[(1R)-1-Hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask was placed a solution ofN-[3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide(1.1 g, 2.25 mmol, 1.00 equiv) in MeOH (50 mL) then Py.HF (6 mL) wasadded. The resulting solution was stirred for 1 h at RT thenconcentrated under reduced pressure. The residue was dissolved in EtOAc(60 mL), washed with NaHCO₃ solution (2×50 mL) and brine (2×50 mL), thendried over anhydrous Na₂SO₄, and concentrated under reduced pressure.The residue was applied onto a silica gel column and eluted withEtOAc/petroleum ether (1:3) affording 150 mg of a mixture of the titlecompounds. The mixture was separated by Chiral-Prep-HPLC (Column:Phenomenex Lux 5 u Cellulose-4, AXIA Packed, 250*21.2 mm, 5 um; MobilePhase A:Hex, Mobile Phase B: EtOH; Flow rate: 20 mL/min; Gradient: 30 Bto 30 B in 27 min; 254/220 nm; RT1:19.83; RT2:23.28) affording 52.6 mgofN-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamideas a white solid and 51.3 mg ofN-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamideas a white solid.

N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide:LC-MS (ES, m/z): [M+H]⁺=375.0. ¹H NMR (300 MHz, DMSO-d₆): δ 9.24-9.20(d, J=7.5 Hz, 1H), 7.80-7.78 (m, 2H), 7.59 (s, 1H), 7.26-7.23 (m, 1H),5.92-5.90 (d, J=5.7 Hz, 1H), 4.93-4.84 (m, 1H), 4.35-4.27 (m, 1H),2.99-2.96 (d, J=6.6 Hz, 2H), 2.47-2.37 (m, 3H), 1.97-1.91 (m, 2H),1.46-1.44 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm): 95.9%.

N-[(1r,3r⁾⁻3-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-3-(thiophen-2-yl)-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=375.0. ¹H NMR (300 MHz, DMSO-d₆): δ 9.32-9.30 (d,J=7.2 Hz, 1H), 7.80-7.78 (d, J=4.5 Hz, 2H), 7.60 (s, 1H), 7.26-7.23 (m,1H), 5.93-5.91(d, J=5.4 Hz, 1H), 4.93-4.85 (m, 1H), 4.58-4.51 (m, 1H),3.10-3.08 (d, J=7.8 Hz, 2H), 2.72-2.65 (m, 1H), 2.83-2.29 (m, 2H),2.18-2.11 (m, 2H), 1.47-1.44 (d, J=6.9 Hz, 3H). Purity (HPLC, 254 nm):99.7%.

Examples 47 and 48N-((1r,3r)-3-((5-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-((1r,3r)-3-((4-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide

Step 1:N-((1r,3r)-3-(Azidomethyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of((1r,3r)-3-(3-phenylisoxazole-5-carboxamido)cyclobutyl)methyl4-methylbenzenesulfonate (1.5 g, 3.52 mmol, 1.00 equiv) in DMF (15 mL)then NaN₃ (390 mg, 6.00 mmol, 1.50 equiv) was added. The resultingsolution was stirred for 5 h at 80° C., quenched by the addition of 20mL of ice/water, and extracted with DCM (2×30 mL). The organic extractswere combined, dried over anhydrous Na₂SO₄, and concentrated underreduced pressure. The residue was applied onto a silica gel column andeluted with EtOAc/petroleum ether (1:20) affording 0.9 g (86%) ofN-((1r,3r)-3-(azidomethyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide asa white solid. LCMS: (ES, m/z): [M+H]⁺=298.1.

Step 2:N-((1r,3r)-3-((5-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideandN-((1r,3r)-3-((4-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution ofN-((1r,3r)-3-(azidomethyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide(700 mg, 2.35 mmol, 1.00 equiv) in DMF (5 mL) then prop-2-yn-1-ol (660mg, 11.77 mmol, 5.00 equiv) was added. The resulting solution wasstirred for 24 h at 80° C., then the solvent was removed under reducedpressure. The residue was applied onto a silica gel column and elutedwith EtOAc/petroleum ether (1:5). The resulting mixture was separated byPrep-SFC (Column: Lux 5 u Celluloes-3, AXIA Packed, 250*21.2 mm; MobilePhase A:CO₂ :70, Mobile Phase B: MeOH:30; Flow rate: 40 mL/min; 220 nm;RT1:4.47; RT2:5.32) affording 120 mg (27%) ofN-((1r,3r)-3-((5-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a white solid and 119.8 mg (27%) ofN-((1r,3r)-3-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamideas a white solid.

N-((1r,3r)-3-((5-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354.1. ¹H NMR (300 MHz, DMSO-d₆): δ 9.29-9.27 (d,J=7.2 Hz, 1H), 8.00 (s, 1H), 7.93-7.90 (m, 2H), 7.63 (s, 1H), 7.55-7.52(m, 3H), 5.17-5.13 (t, J=5.7 Hz, 1H), 4.60-4.49 (m, 5H), 2.74-2.70 (m,1H), 2.31-2.12 (m, 4H). Purity (HPLC, 254 nm): 98.8%.

N-((1r,3r)-3-((4-(Hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)cyclobutyl)-3-phenylisoxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354. ¹H NMR (300 MHz, DMSO-d₆): δ 9.30-9.27 (d,J=7.5 Hz, 1H), 7.93-7.90 (m, 2H), 7.63-7.60 (m, 2H), 7.57-7.52 (m, 5H),5.51-5.47 (t, J=5.7 Hz, 1H), 4.66-4.60 (m, 3H), 4.53-4.47(m, 2H),2.86-2.78 (m, 1H), 2.30-2.15 (m, 4H). Purity (HPLC, 254 nm): 96.9%.

Example 493-Phenyl-N-[(1r,3r)-3-[5-(oxetan-2-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1:3-Phenyl-N-[(1r,3r)-3-(hydrazinecarbonyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 100-mL round-bottom flask was placed a solution of(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid(2.87 g, 10.03 mmol, 1.00 equiv) in THF (50 mL), then CDI (3.24 g, 20.00mmol, 2.00 equiv) was added. The resulting solution was stirred for 1 hat 25° C. and then N₂H₄.H₂O (2.1 g, 30.00 mmol, 3.00 equiv) was added.The resulting solution was stirred for 16 h at RT then diluted with 300mL of H₂O. The solids were collected by filtration and dried in an ovenunder reduced pressure affording 487 mg (16%) of3-phenyl-N-[1r,3r)-3-(hydrazinecarbonyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid. LCMS (ES, m/z): [M+H]⁺=301.1.

Step 2:3-Phenyl-N-[(1r,3r)-3-[(oxetan-2-ylformohydrazido)carbonyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution of3-phenyl-N-[(1r,3r)-3-(hydrazinecarbonyl)cyclobutyl]-1,2-oxazole-5-carboxamide(280 mg, 0.93 mmol, 1.00 equiv) in DMF (5 mL) then HATU (570 mg, 1.50mmol, 1.50 equiv), DIEA (361 mg, 2.79 mmol, 3.00 equiv) andoxetane-2-carboxylic acid (143 mg, 1.40 mmol, 1.50 equiv) were added.The resulting solution was stirred for 2 h at RT then diluted with 50 mLof H₂O and extracted with EtOAc (2×50 mL). The organic extracts werecombined, washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The crude product was purified byPrep-TLC (petroleum ether/ethyl acetate=1:2) affording 220 mg (61%) of3-phenyl-N-[(1r,3r)-3-[(oxetan-2-ylformohydrazido)carbonyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid. LCMS (ES, m/z):[M+H]⁺=385.1.

Step 3:3-Phenyl-N-[(1r,3r)-3-[5-(oxetan-2-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask was placed a solution of PPh₃(299 mg, 1.14 mmol, 2.00 equiv) in DCM (20 mL), then I₂ (290 mg, 1.14mmol, 2.00 equiv) and TEA (230 mg, 2.27 mmol, 4.00 equiv) were added.The resulting solution was stirred for 10 min at RT then3-phenyl-N-[1r,3r)-3-[(oxetan-2-ylformohydrazido)carbonyl]cyclobutyl]-1,2-oxazole-5-carboxamide(220 mg, 0.57 mmol, 1.00 equiv) was added and stirred for 1 h at rt. Thereaction was diluted with 100 mL of H₂O and extracted with EtOAc (2×100mL). The organic extracts were combined, washed with brine (2×100 mL),dried over anhydrous Na₂SO₄, and concentrated under reduced pressure.The residue was applied onto a silica gel column and eluted withEtOAc/petroleum ether (2:1) affording 174.8 mg (83%) of3-phenyl-N-[(1r,3r)-3-[5-(oxetan-2-yl)-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas an off-white solid. LCMS (ES, m/z): [M+H]⁺=367.3. ¹H NMR (400 MHz,DMSO-d₆) δ 9.45 (d, J=7.2 Hz, 1H), 7.93-7.91 (m, 2H), 7.65 (s, 1H),7.54-7.52 (m, 3H), 5.88-5.84 (t, J=7.6 Hz, 1H), 4.72-4.62 (m, 3H),3.81-3.74 (m, 1H), 3.12-2.96 (m, 2H), 2.73-2.66 (m, 4H). Purity (HPLC,254 nm): 99.5%.

Example 504-Fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: Methyl 3-Phenyl-1,2-oxazole-5-carboxylate. To a 50-mLround-bottom flask was placed a solution of3-phenyl-1,2-oxazole-5-carboxylic acid (1.89 g, 9.99 mmol, 1.00 equiv)in DCM (20 mL) then oxalyl chloride (1.9 g, 14.97 mmol, 1.50 equiv) anda drop of DMF were added. The resulting solution was stirred for 1 h atRT then MeOH (5 mL) was added. The reaction was stirred for 1 h at RTthen concentrated under reduced pressure affording 1.9 g (94%) of methyl3-phenyl-1,2-oxazole-5-carboxylate as a yellow solid.

Step 2: Methyl 4-Fluoro-3-phenyl-1,2-oxazole-5-carboxylate. To a 25-mLround-bottom flask was placed a solution of methyl3-phenyl-1,2-oxazole-5-carboxylate (1 g, 4.92 mmol, 1.00 equiv) insulfone (10 mL) then Selectfluor (3.54 g, 10.00 mmol, 2.00 equiv) wasadded. The resulting solution was stirred for 16 h at 120° C., dilutedwith 100 mL of H₂O, and extracted with EtOAc (2×100 mL). The organicextracts were combined, washed with brine (2×100 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure. The crudeproduct was purified by Prep-TLC (petroleum ether/ethyl acetate=10:1)affording 250 mg (25%) of methyl4-fluoro-3-phenyl-1,2-oxazole-5-carboxylate as a white solid. LCMS (ES,m/z): [M+H]⁺=222.0.

Step 3: 4-Fluoro-3-phenyl-1,2-oxazole-5-carboxylic acid. To a 25-mLround-bottom flask was placed a solution of methyl4-fluoro-3-phenyl-1,2-oxazole-5-carboxylate (250 mg, 1.13 mmol, 1.00equiv) in THF/H₂O (10/3 mL) then LiOH (82 mg, 3.42 mmol, 3.00 equiv) wasadded. The resulting solution was stirred for 2 h at RT and then dilutedwith 50 mL of H₂O. The pH of the solution was adjusted to 4-5 usingconcentrated 12M HCl, then extracted with EtOAc (2×50 mL). The organicextracts were combined, washed with brine (2×50 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure affording 210mg (90%) of 4-fluoro-3-phenyl-1,2-oxazole-5-carboxylic acid as a whitesolid.

Step 3:4-Fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1S)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of4-fluoro-3-phenyl-1,2-oxazole-5-carboxylic acid (210 mg, 1.01 mmol, 1.00equiv) in DCM (10 mL), then HATU (570 mg, 1.50 mmol, 1.50 equiv),(1r,3r)-3-5-[(1S)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-ylcyclobutan-1-amine(300 mg, 1.01 mmol, 1.00 equiv) and DIEA (387 mg, 2.99 mmol, 3.00 equiv)were added. The resulting solution was stirred for 1 h at RT, dilutedwith 100 mL of H₂O, and extracted with EtOAc (2×100 mL). The organicextracts were combined, washed with brine (2×100 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure. The residuewas applied onto a silica gel column and eluted with EtOAc/petroleumether (1:5) affording 360 mg (73%) of4-fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1S)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=487.3.

Step 4:4-Fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution of4-fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamide(360 mg, 0.74 mmol, 1.00 equiv) in methanol (6 mL) then Py.HF (2 mL) wasadded. The resulting solution was stirred for 1 h at RT then dilutedwith 50 mL of H₂O, and extracted with EtOAc (2×50 mL). The organicextracts were combined, washed with brine (3×50 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure. The crudeproduct was purified by Prep-HPLC (HPLC-10: Column, X Bridge C18 OBDPrep Column, 19 mm×250 mm; mobile phase, Water (0.5% NH₄HCO₃) and ACN(30.0% ACN up to 50.0% in 8 min); Detector, UV 254/220 nm) affording133.3 mg (48%) of4-fluoro-3-phenyl-N-[(1r,3r)-3-[5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=372.9. ¹H NMR (400 MHz,DMSO-d₆) δ 9.49-9.47 (d, J=7.2 Hz, 1H), 7.99-7.94 (m, 1H), 7.65-7.60 (m,1H), 7.52 (s, 1H), 7.48-7.37 (m, 2H), 5.96-5.95 (d, J=6.4 Hz, 1H),4.95-4.89 (m, 1H), 4.70-4.64 (m, 1H), 3.78-3.72 (m, 1H), 2.72-2.63 (m,4H), 1.49-1.48 (d, J=6.8 Hz, 3H). Purity (HPLC, 254 nm): 99.7%.

Examples 51 and 523-Phenyl-N-[(1s,3s)-3-[5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-[4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: tert-Butyl N-(3-Oxocyclobutyl)carbamate. To a 1000-mL 3-neckedround-bottom flask was placed a solution of3-oxocyclobutane-1-carboxylic acid (20 g, 175.29 mmol, 1.00 equiv) intoluene (400 mL), then TEA (19.5 g, 192.71 mmol, 1.10 equiv) and DPPA(53 g, 192.73 mmol, 1.10 equiv) were added. The resulting solution wasstirred overnight at 0° C., then washed with saturated sodiumbicarbonate aqueous (2×120 mL), H₂O (1×120 mL), and brine (1×60 mL) at0˜10° C. The solution was dried over anhydrous Na₂SO₄ and filtered. Tothis solution was added t-BuOH (100 mL) and then the reaction wasstirred for 16 h at 100° C. The solvent was removed under reducedpressure then the residue was washed with TBME (60 mL) affording 8.3 g(26%) of tert-butyl N-(3-oxocyclobutyl)carbamate as a light white solid.¹H NMR (400 MHz, CDCl₃) δ 4.94 (brs, 1H), 4.29 (brs, 1H), 3.48-3.36 (m,2H), 3.13-3.01 (m, 2H), 1.48 (s, 9H).

Step 2: tert-Butyl N-[(1s,3s)-3-Hydroxycyclobutyl]carbamate. To a 250-mLround-bottom flask was placed a solution of tert-butylN-(3-oxocyclobutyl)carbamate (8.3 g, 44.81 mmol, 1.00 equiv) inTHF/H₂O=9:1 (100 mL) then NaBH₄ (830 mg, 22.54 mmol, 0.50 equiv) wasadded in portions at −70° C. The resulting solution was stirred for 1 hat −50° C. then the reaction was quenched by the addition of water. Themixture was extracted with EtOAc, the organic extracts were combined andthe solvent was removed under reduced pressure. The residue wasdissolved in 20 mL of toluene at 80° C., then the solution was cooled toRT and stirred for 1 h. The solids were collected by filtrationaffording 7.56 g (90%) of tert-butylN-[(1s,3s)-3-hydroxycyclobutyl]carbamate as a white solid. ¹H NMR (400MHz, CDCl₃) δ 4.67 (brs, 1H), 4.08-4.01 (m, 1H), 3.69-3.66 (m, 1H),2.82-2.76 (m, 2H), 2.00 (brs, 1H), 1.88-1.75 (m, 2H), 1.46 (s, 9H).

Step 3:((1r,3r)-3-[[(tert-Butoxy)carbonyl]amino]cyclobutyl-4-nitrobenzoate. Toa 250-mL 3-necked round-bottom flask purged and maintained with an inertatmosphere of nitrogen was placed a solution of tert-butylN-[(1s,3s)-3-hydroxycyclobutyl]carbamate (7.56 g, 40.38 mmol, 1.00equiv) in THF (100 mL), then PPh₃ (15.89 g, 60.58 mmol, 1.50 equiv) andPNBA (7.43 g, 1.10 equiv) were added. This was followed by the additionof DIAD (12.25 g, 60.58 mmol, 1.50 equiv) dropwise with stirring at 0°C. The resulting solution was stirred overnight at RT, then the reactionwas quenched by the addition of water and extracted with EtOAc. Theorganic extracts were combined and then concentrated under reducedpressure. The residue was dissolved in 10 mL of EtOH and stirred for 2 hat RT. The solids were collected by filtration affording 10.8 g (80%) of(1r,3r)-3-[[(tert-butoxy)carbonyl]amino]cyclobutyl 4-nitrobenzoate as awhite solid. ¹H NMR (300 MHz, CDCl₃) δ 8.28-8.17 (m, 4H), 5.36-5.32 (m,1H), 4.77 (brs, 1H), 4.36 (brs, 1H), 2.65-2.56 (m, 2H), 2.47-2.38 (m,2H), 1.43 (s, 9H).

Step 4: (1r,3r)-3-Aminocyclobutyl 4-nitrobenzoate trifluoroacetic acidsalt. To a 100-mL round-bottom flask was placed a solution of(1r,3r)-3-[[(tert-butoxy)carbonyl]amino[cyclobutyl 4-nitrobenzoate (10.8g, 32.11 mmol, 1.00 equiv) in DCM (25 mL) and TFA (7 mL). The resultingsolution was stirred overnight at RT, then the solvent was removed underreduced pressure affording 10.3 g (92%) of (1r,3r)-3-aminocyclobutyl4-nitrobenzoate trifluoroacetic acid salt as a white solid. ¹H NMR (300MHz, CD₃OD) δ 8.28-8.25 (m, 4H), 5.52-5.44 (m, 1H), 4.09-4.00 (m, 1H),2.85-2.62 (m, 4H).

Step 5: (1r,3r)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutyl4-nitrobenzoate. To a 250-mL round-bottom flask was placed a solution of(1r,3r)-3-aminocyclobutyl 4-nitrobenzoate trifluoroacetic acid salt (4g, 11.42 mmol, 1.00 equiv), DIEA (7.4 g, 57.26 mmol, 5.00 equiv) and3-phenyl-1,2-oxazole-5-carboxylic acid (2.6 g, 13.74 mmol, 1.20 equiv)in DCM (100 mL). To this solution was added HATU (6.5 g, 17.09 mmol,1.50 equiv), then the reaction was stirred for 30 min at RT. Thereaction was quenched with H₂O and extracted with EtOAc. The organicextracts were combined, washed with brine, dried over anhydrous Na₂SO₄,and concentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:5) affording4.57 g (98%) of (1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl4-nitrobenzoate as a white solid. LCMS (ES, m/z): [M+H]⁺=408.1.

Step 6:3-Phenyl-N-[(1r,3r)-3-hydroxycyclobutyl]-1,2-oxazole-5-carboxamide. To a100-mL round-bottom flask was placed a solution of(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl 4-nitrobenzoate (4.4g, 10.80 mmol, 1.00 equiv) in MeOH/H₂O=2:1 (30 mL), then K₂CO₃ (4.4 g,31.83 mmol, 3.00 equiv) was added. The resulting mixture was stirredovernight at 40° C. The reaction was quenched with H₂O and thenextracted with EtOAc. The organic extracts were combined, washed withbrine, dried over Na₂SO₄, and then concentrated under reduced pressureaffording 2.2 g (79%) of3-phenyl-N-[(1r,3r)-3-hydroxycyclobutyl]-1,2-oxazole-5-carboxamide as awhite solid. LCMS (ES, m/z): [M+H]⁺=259.1.

Step 7:3-Phenyl-N-[(1s,3s)-3-azidocyclobutyl]-1,2-oxazole-5-carboxamide. To a100-mL round-bottom flask was placed a solution of3-phenyl-N-[(1r,3r)-3-hydroxycyclobutyl]-1,2-oxazole-5-carboxamide (2.2g, 8.52 mmol, 1.00 equiv), DPPA (2.8 g, 10.17 mmol, 1.20 equiv) and PPh₃(3.3 g, 12.58 mmol, 1.50 equiv) in THF (40 mL), then DIAD (2.6 g, 12.86mmol, 1.50 equiv) was added dropwise. The reaction was stirred for 1 hat 30° C., quenched by the addition of brine, and extracted with EtOAc.The organic extracts were combined, dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with ethyl acetate/petroleum ether (1:10)affording 860 mg (36%) of3-phenyl-N-[(1s,3s)-3-azidocyclobutyl]-1,2-oxazole-5-carboxamide as awhite solid.

Step 8:3-Phenyl-N-[(1s,3s)-3-[5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-[4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 10-mL sealed tube was placed a solution of3-phenyl-N-[(1s,3s)-3-azidocyclobutyl]-1,2-oxazole-5-carboxamide (550mg, 1.94 mmol, 1.00 equiv) in DMF (2.5 mL), then (2R)-but-3-yn-2-ol (680mg, 9.70 mmol, 5.00 equiv) was added. The resulting solution was stirredovernight at 100° C. After removing the solvent under reduced pressure,the residue was applied onto a silica gel column with ethylacetate/petroleum ether (1:3). The resulting mixture was separated byPrep-SFC (Prep SFC80-1: Column, Chiralpak AD-H, 2*25 cm; mobile phase,CO₂ (50%) and ethanol (50%); Detector, UV 220 nm) affording 170.0 mg(25%) of3-phenyl-N-[(1s,3s)-3-[5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 222 mg (32%) of3-phenyl-N-[(1s,3s)-3-[4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-[5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354. ¹H NMR (300 MHz, DMSO-d₆) δ 9.50-9.47 (d,J=7.2 Hz, 1H), 7.94-7.90 (m, 2H), 7.66 (s, 1H), 7.61 (s, 1H), 7.56-7.54(m, 3H), 5.52-5.50 (d, J=6.0 Hz, 1H), 4.95-4.85 (m, 2H), 4.45-4.31 (m,1H), 2.94-2.80 (m, 4H), 1.45-1.43 (d, J=6.6 Hz, 3H). Purity (HPLC, 254nm): 99.4%.

3-Phenyl-N-[(1s,3s)-3-[4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354. ¹H NMR (300 MHz, DMSO-d₆) δ 9.41-9.39 (d,J=8.4 Hz, 1H), 8.13 (s, 1H), 7.96-7.93 (m, 2H), 7.68 (s, 1H), 7.56-7.54(m, 3H), 5.30-5.28 (d, J=4.8 Hz, 1H), 5.00-4.80 (m, 2H), 4.48-4.35 (m,1H), 2.98-2.89 (m, 2H), 2.74-2.64 (m, 2H), 1.43-1.41 (d, J=6.6 Hz, 3H).

Examples 53 and 543-Phenyl-N-[(1s,3s)-3-[5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-[4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1:3-Phenyl-N-[(1s,3s)-3-[5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-[4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 10-mL sealed tube, was placed a solution of3-phenyl-N-[(1s,3s)-3-azidocyclobutyl]-1,2-oxazole-5-carboxamide (500mg, 1.77 mmol, 1.00 equiv) in DMF (2.5 mL), then (2S)-but-3-yn-2-ol (618mg, 8.82 mmol, 5.00 equiv) was added. The reaction was stirred overnightat 100° C. then concentrated under reduced pressure. The residue wasapplied onto a silica gel column with EtOAc/petroleum ether (1:3). Theresulting mixture was separated by Prep-SFC (Prep SFC80-1: Column,Chiralpak AD-H, 2*25 cm; mobile phase, CO2(55%) and methanol(45%);Detector, UV 220 nm) affording 106.1 mg (17%) of3-phenyl-N-[(1s,3s)-3-[5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 192.2 mg (31%) of3-phenyl-N-[(1s,3s)-3-[4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-[5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354. ¹H NMR (300 MHz, DMSO-d₆) δ 9.50-9.47 (d,J=7.5 Hz, 1H), 7.94-7.90 (m, 2H), 7.66 (s, 1H), 7.61 (s, 1H), 7.56-7.54(m, 3H), 5.52-5.50 (d, J=6.0 Hz, 1H), 4.95-4.85 (m, 2H), 4.45-4.31 (m,1H), 2.94-2.80 (m, 4H), 1.45-1.43 (d, J=6.3 Hz, 3H). Purity (HPLC, 254nm): 96.0%.

3-Phenyl-N-[(1s,3s)-3-[4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=354. ¹H NMR (300 MHz, DMSO-d₆) δ 9.41-9.39 (d,J=8.1 Hz, 1H), 8.13 (s, 1H), 7.96-7.93 (m, 2H), 7.68 (s, 1H), 7.56-7.54(m, 3H), 5.30-5.28 (d, J=4.5 Hz, 1H), 5.00-4.92 (m, 1H), 4.88-4.80 (m,1H), 4.48-4.35 (m, 1H), 2.98-2.89 (m, 2H), 2.74-2.50 (m, 2H), 1.43-1.41(d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm): 97.7%.

Examples 55 and 563-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: tert-Butyl(1s,3s)-3-(1,3-Dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylate.To a 250-mL 3-necked round-bottom flask was placed a solution oftert-butyl (1r,3r)-3-hydroxycyclobutane-1-carboxylate (1.1 g, 5.87 mmol,1.00 equiv), 2,3-dihydro-1H-isoindole-1,3-dione (1.04 g, 7.07 mmol, 1.19equiv), and PPh₃ (2.5 g) in THF (60 mL). This was followed by theaddition of DIAD (300 mg) dropwise with stirring at 0° C. The resultingsolution was stirred for 1 h at RT then the reaction was quenched by theaddition of 50 mL of water. The resulting solution was extracted withEtOAc (3×50 mL) and the organic layers combined. The resulting mixturewas washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:40) affording810 mg of tert-butyl(1s,3s)-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylateas a white solid. LCMS (ES, m/z): [M+H]⁺=302.2.

Step 2: tert-Butyl (1s,3s)-3-Aminocyclobutane-1-carboxylate. To a2000-mL round-bottom flask was placed a solution of tert-butyl(1s,3s)-3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)cyclobutane-1-carboxylate(810 mg, 2.64 mmol, 1.00 equiv) in EtOH (50 mL) and then N₂H₄.H₂O (400mg, 3.00 equiv) was added. The resulting solution was stirred for 4 h atRT, then the solids were removed by filtration. The filtrate wasconcentrated under reduced pressure affording 500 mg of crude tert-butyl(1s,3s)-3-aminocyclobutane-1-carboxylate as light yellow oil. LCMS[M+H]⁺=172.1

Step 3: tert-Butyl(1s,3s)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate. To a100-mL round-bottom flask was placed a solution of tert-butyl(1s,3s)-3-aminocyclobutane-1-carboxylate (1.7 g, 9.93 mmol, 1.00 equiv)in DCM (50 mL), then 3-phenyl-1,2-oxazole-5-carboxylic acid (1.9 g,10.04 mmol, 1.00 equiv), HATU (5.7 g, 14.99 mmol, 1.50 equiv) and DIEA(3.9 g, 30.18 mmol, 3.00 equiv) were added. The resulting solution wasstirred for 1 h at RT, then quenched by the addition of water andextracted with EtOAc. The organic extracts were combined, washed withbrine, dried over anhydrous Na₂SO₄, and concentrated under reducedpressure. The residue was applied onto a silica gel column and elutedwith EtOAc/petroleum ether (1:7) affording 2 g (59%) of tert-butyl(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate as awhite solid. LCMS (ES, m/z): [M+H]⁺=343.2.

Step 4: (1s,3s)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylicacid. To a 25-mL round-bottom flask was placed a solution of tert-butyl(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate (830mg, 2.42 mmol, 1.00 equiv) in DCM (10 mL) and TFA (3 mL). The resultingsolution was stirred for 2 h at rt, then the reaction was concentratedunder reduced pressure affording 680 mg (98%) of(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid asa light yellow solid.

Step 5:3-Phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask was placed a solution of(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid(1.2 g, 4.19 mmol, 1.00 equiv) in THF (50 mL) followed by the additionof LiAlH₄ (319 mg, 8.41 mmol, 2.00 equiv) in portions at 0° C. over 5min The resulting solution was stirred for 2 h at RT, then quenched bythe addition of 100 mL of 2N HCl, and extracted with EtOAc (2×100 mL).The organic extracts were combined, washed with brine (2×100 mL), driedover anhydrous Na₂SO₄, and concentrated under reduced pressure affording860 mg (75%) of3-phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid. LCMS (ES, m/z): [M+H]⁺=273.1.

Step 6: [(1s,3s)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate. To a 50-mL round-bottom flask was placed asolution of3-phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(860 mg, 3.16 mmol, 1.00 equiv) in DCM (20 mL) then DMAP (781 mg, 6.39mmol, 2.00 equiv) and TsCl (779 mg, 4.09 mmol, 1.30 equiv) were added.The resulting solution was stirred for 16 h at RT, diluted with 100 mLof H₂O, and extracted with EtOAc (2×100 mL). The organic extracts werecombined, washed with brine (2×100 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure affording 1.1 g (82%) of[(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate as a yellow solid. LCMS (ES, m/z):[M+H]⁺=427.2.

Step 7:3-Phenyl-N-[(1s,3s)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution of[(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (1.1 g, 2.58 mmol, 1.00 equiv) in DMF (10mL), then NaN₃ (254 mg, 3.91 mmol, 1.50 equiv) was added. The resultingsolution was stirred for 1 h at 80° C., diluted with 100 mL of H₂O, andextracted with EtOAc (2×100 mL). The organic extracts were combined,washed with brine (5×100 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure affording 750 mg (98%) of3-phenyl-N-[(1s,3s)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid.

Step 8:3-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution of3-phenyl-N-[(1s,3s)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(350 mg, 1.18 mmol, 1.00 equiv) in DMF (5 mL), then (2R)-but-3-yn-2-ol(420 mg, 5.99 mmol, 5.00 equiv) was added. The resulting solution wasstirred for 16 h at 80° C., then diluted with 50 mL of H₂O, andextracted with EtOAc (3×50 mL). The organic extracts were combined,washed with brine (3×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (5:1). The pureisomers were separated by Chiral-Prep-HPLC (Prep-HPLC-009: Column,Chiralpak IB, 2*25 cm, 5 um; mobile phase, Hex and ethanol (hold 15.0%ethanol in 29 min); Detector, UV 254/220 nm) affording 29.4 mg (7%) of3-phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid and 31.6 mg (7%) of3-phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.1. ¹H NMR (300 MHz, DMSO-d₆) δ 9.25-9.22 (d,J=7.8 Hz, 1H), 7.94-7.91 (m, 2H), 7.63-7.60 (d, J=6.9 Hz, 2H), 7.55-7.53(m, 3H), 5.53-7.51 (d, J=6.0 Hz, 1H), 4.93-4.85 (m, 1H), 4.43-4.40 (d,J=7.2 Hz, 2H), 4.35-4.27 (m, 1H), 2.64-2.55 (m, 1H), 2.39-2.30 (m, 2H),2.03-1.94 (m, 2H), 1.48-1.46 (d, J=6.3 Hz, 3H). Purity (HPLC, 254 nm):95.2%.

3-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.1. ¹H NMR (300 MHz, DMSO-d₆) δ 9.22-9.19 (d,J=7.8 Hz, 1H), 7.90-7.76 (m, 2H), 7.84 (s, 1H), 7.59 (s, 1H), 7.55-7.46(m, 3H), 5.19-5.18 (d, J=4.5 Hz, 1H), 4.80-4.76 (m, 1H), 4.35-4.24 (m,3H), 2.60-2.50 (m, 1H), 2.33-2.25 (m, 2H), 1.95-1.88 (m, 2H), 1.37-1.35(d, J=6.3 Hz, 3H). Purity (HPLC, 254 nm): 95.0%.

Examples 57 and 583-Phenyl-N-[(1s,3s)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide.

Into a 25-mL round-bottom flask, was placed a solution of3-phenyl-N-[(1s,3s)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(270 mg, 0.91 mmol, 1.00 equiv) in toluene (5 mL), then(2S)-but-3-yn-2-ol (315 mg, 4.49 mmol, 5.00 equiv) was added. Theresulting solution was stirred for 16 h at 100° C. and then concentratedunder reduced pressure. The crude product was purified by Prep-TLC(petroleum ether/EtOAc=1:5). The resulting mixture was separated byChiral-Prep-HPLC (2#-Gilson Gx 281(HPLC-09): Column: Chiralpak IB, 2*25cm, 5 um; Mobile Phase A: hexane, Mobile Phase B: EtOH; Flow rate: 20ml/min; Gradient: 30 B to 30 B in 15 min; 254/220 nm; RT1:7.642;RT2:10.588) affording 32.8 mg (10%) of3-phenyl-N-[(1s,3s)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 68.5 mg (21%) of3-phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1s,3s)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.24-9.22 (d,J=7.6 Hz, 1H), 7.94-7.92 (m, 2H), 7.62-7.60 (d, J=8.4 Hz, 1H), 7.55-7.53(m, 3H), 5.52-5.50 (d, J=6.0 Hz, 1H), 4.95-4.83 (m, 1H), 4.43-4.40 (m,2H), 4.35-4.31 (m, 3H), 2.54-2.52 (m, 1H), 2.36-2.33 (m, 2H), 2.05-1.98(m, 2H), 1.48-1.46 (d, J=6.4 Hz, 3H). Purity (HPLC, 254 nm): 93.1%.

3-Phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.24-9.22 (d,J=7.6 Hz, 1H), 7.94-7.92 (m, 2H), 7.87 (s, 1H), 7.62 (s, 1H), 7.55-7.53(m, 3H), 5.22-5.21 (d, J=4.8 Hz, 1H), 4.85-4.79 (m, 1H), 4.38-4.37 (d,J=7.2 Hz, 2H), 4.34-4.28 (m, 1H), 2.54-2.46 (m, 1H), 2.39-2.32 (m, 2H),2.01-1.93 (m, 2H), 1.41-1.39 (d, J=6.4 Hz, 3H). Purity (HPLC, 254 nm):98.6%.

Examples 59 and 603-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1:3-Phenyl-N-[(1r,3r)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 25-mL round-bottom flask was placed a solution of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (920 mg, 2.16 mmol, 1.00 equiv) in DMF (10mL), then NaN₃ (169 mg, 2.60 mmol, 1.20 equiv) was added. The resultingsolution was stirred for 2 h at 80° C., then diluted with 100 mL of H₂O,and extracted with EtOAc (2×50 mL). The organic extracts were combined,washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure affording 600 mg (94%) of3-phenyl-N-[(1r,3r)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid.

Step 2:3-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 5-mL round-bottom flask was placed a solution of3-phenyl-N-[(1r,3r)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(300 mg, 1.01 mmol, 1.00 equiv) in DMF (5 mL), then (2R)-but-3-yn-2-ol(210 mg, 3.00 mmol, 3.00 equiv) was added. The resulting solution wasstirred for 16 h at 100° C., then diluted with 50 mL of H₂O, andextracted with EtOAc (2×50 mL). The organic extracts were combined,washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The crude product was purified byPrep-TLC (petroleum ether/ethyl acetate=1:5). The resulting mixture wasseparated by Chiral-Prep-HPLC (Prep-HPLC-004: Column, Chiralpak IA, 2*25cm, 5 um; mobile phase, Hex and IPA (hold 30.0% IPA in 15 min);Detector, UV 254/220 nm) affording 103.5 mg (28%) of3-phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 127.1 mg (38%) of3-phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a light yellow solid.

3-Phenyl-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideLCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.29-9.27 (d,J=7.2 Hz, 1H), 7.92-7.90 (m, 2H), 7.62-7.59 (m, 2H), 7.53-7.52 (m, 3H),5.53-5.52 (d, J=6.0 Hz, 1H), 4.92-4.89 (m, 1H), 4.62-4.58 (m, 1H),4.56-4.48 (m, 2H), 2.85-2.81 (m, 1H), 2.27-2.17 (m, 4H), 1.46-1.44 (d,J=6.4 Hz, 3H). Purity (HPLC, 254 nm): 95.0%.

3-Phenyl-N-[(1r,3r)-3-([4[(1R)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideLCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.27-9.25 (d,J=7.2 Hz, 1H), 7.94 (s, 1H), 7.93-7.89 (m, 2H), 7.62 (s, 1H), 7.53-7.51(m, 3H), 5.21-5.20 (d, J=4.8 Hz, 1H), 4.83-4.80 (m, 1H), 4.59-4.51 (m,1H), 4.48-4.46 (d, J=7.6 Hz, 2H), 2.74-2.66 (m, 1H), 2.28-2.21 (m, 2H),2.17-2.11 (m, 2H), 1.39-1.37 (d, J=6.8 Hz, 3H). Purity (HPLC, 254 nm):96.9%.

Examples 61 and 623-Phenyl-N-[(1r,3r)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

To a 25-mL round-bottom flask was placed a solution of3-phenyl-N-[(1r,3r)-3-(azidomethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(210 mg, 0.71 mmol, 1.00 equiv) in toluene (5 mL), then(2S)-but-3-yn-2-ol (245 mg, 3.50 mmol, 5.00 equiv)was added. Theresulting solution was stirred for 16 h at 100° C., then concentratedunder reduced pressure. The crude product was purified by Prep-TLC(petroleum ether/EtOAc=1:5). The resulting mixture was separated byChiral-Prep-HPLC (Prep-HPLC-004: Column, Chiralpak IC, 2*25 cm, 5 um;mobile phase, Hex and ethanol (hold 50.0% ethanol in 15 min); Detector,UV 254/220 nm) affording 44.2 mg (17%) of3-phenyl-N-[(1r,3r)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 78.5 mg (30%) of3-phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-Phenyl-N-[(1r,3r)-3-([5-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.31-9.29 (d,J=7.2 Hz, 1H), 7.94-7.91 (m, 2H), 7.64-7.60 (m, 2H), 7.55-7.52 (m, 3H),5.55-5.53 (d, J=6.0 Hz, 1H), 4.95-4.89 (m, 1H), 4.64-4.47 (m, 3H),2.88-2.82 (m, 1H), 2.30-2.19 (m, 4H), 1.48-1.46 (d, J=6.4 Hz, 3H).Purity (HPLC, 254 nm): 97.5%.

3-Phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-1,2,3-triazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=368.2. ¹H NMR (400 MHz, DMSO-d₆) δ 9.30-9.28 (d,J=7.6 Hz, 1H), 7.96 (s, 1H), 7.94-7.91 (m, 2H), 7.64 (s, 1H), 7.55-7.53(m, 3H), 5.23-5.21 (d, J=4.8 Hz, 1H), 4.85-4.79 (m, 1H), 4.58-4.53 (m,1H), 4.50-4.48 (d, J=7.6 Hz, 2H), 2.75-2.71 (m, 1H), 2.30-2.23 (m, 2H),2.18-2.12 (m, 2H), 1.41-1.39 (d, J=6.4 Hz, 3H). Purity (HPLC, 254 nm):99.2%.

Examples 63 and 643-Phenyl-N-[(1r,3r)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-Phenyl-N-[(1r,3r)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1:3-Phenyl-N-[(1r,3r)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (1.28 g, 3.00 mmol, 1.00 equiv) in DMF (20mL), then Cs₂CO₃ (1.95 g, 5.98 mmol, 2.00 equiv) and1H-pyrazole-3-carbaldehyde (432 mg, 4.50 mmol, 1.50 equiv) were added.The resulting solution was stirred for 3 h at 100° C., then the solidswere removed by filtration. The filtrate was purified by Flash-Prep-HPLC(CombiFlash-1: Column, C18; mobile phase, X: H₂O (0.5% NH₄HCO₃), Y: CAN,X/Y=90/10 increasing to X/=5/95 within 40 min; Detector, UV 254 nm)affording 450 mg (43%) of3-phenyl-N-[(1r,3r)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid. LCMS (ES, m/z): [M+H]⁺=351.2.

Step 2:3-Phenyl-N-[(1r,3r)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-phenyl-N-[(1r,3r)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak). To a 50-mL 3-necked round-bottom flask was placed asolution of3-phenyl-N-[(1r,3r)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide(450 mg, 1.28 mmol, 1.00 equiv) in THF (20 mL). The solution was cooledto 0° C., then MeMgBr (1.3 mL, 3.00 equiv, 3 mol/L) was added dropwisewith stirring at 0° C. over 10 min. The reaction was stirred for 2 h atRT, then quenched by the addition of 10 mL of 2N HCl and 50 mL of H₂O,and extracted with EtOAc (3×50 mL). The organic extracts were combined,washed with brine (3×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (2:1). Theresulting mixture was separated by Chiral-Prep-HPLC (Prep-HPLC-004:Column, Chiralpak IC, 2*25 cm, 5 um; mobile phase, Hex and ethanol (hold50.0% ethanol in 13 min); Detector, UV 254/220 nm) affording 126.1 mg(27%) of3-phenyl-N-[(1r,3r)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) as a light yellow solid and 136.9 mg (29%) of3-phenyl-N-[(1r,3r)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak) as a white solid.

3-Phenyl-N-[(1r,3r)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=367.0. ¹H NMR (300 MHz, DMSO-d₆) δ 9.28-9.25 (d,J=7.2 Hz, 1H), 7.94-7.91 (m, 2H), 7.65-7.63 (m, 2H), 7.55-7.53 (m, 3H),6.15-6.14 (d, J=1.8 Hz, 1H), 4.95-4.93 (d, J=4.8 Hz, 1H), 4.72-4.64 (m,1H), 4.58-4.45 (m, 1H), 4.19-4.16 (d, J=7.8 Hz, 2H), 2.72-2.64 (m, 1H),2.27-2.12 (m, 4H), 1.34-1.32 (d, J=6.3 Hz, 3H). Purity (HPLC, 254 nm):98.9%.

3-Phenyl-N-[(1r,3r)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=367.0. ¹H NMR (300 MHz, DMSO-d₆) δ 9.28-9.25 (d,J=7.5 Hz, 1H), 7.94-7.91 (m, 2H), 7.65-7.63 (m, 2H), 7.55-7.53 (m, 3H),6.15-6.14 (d, J=2.1 Hz, 1H), 4.95-4.93 (d, J=5.1 Hz, 1H), 4.72-4.63 (m,1H), 4.55-4.48 (m, 1H), 4.19-4.16 (d, J=7.5 Hz, 2H), 2.69-2.64 (m, 1H),2.27-2.11 (m, 4H), 1.34-1.32 (d, J=6.3 Hz, 3H). Purity (HPLC, 254 nm):98.3%.

Examples 65 and 663-Phenyl-N-[(1s,3s)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-Phenyl-N-[(1s,3s)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak)

Step 1:3-Phenyl-N-[(1s,3s)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of [(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (1.3 g, 3.05 mmol, 1.00 equiv) in DMF (15mL), then Cs₂CO₃ (1.96 g, 6.02 mmol, 2.00 equiv) and1H-pyrazole-3-carbaldehyde (432 mg, 4.50 mmol, 1.50 equiv) were added.The resulting solution was stirred for 3 h at 100° C., then the solidswere removed by filtration. The filtrate was purified by Flash-Prep-HPLC(CombiFlash-1: Column, C18; mobile phase, X: H₂O (0.5% NH₄HCO₃), Y: ACN,X/Y=90/10 increasing to X/ACN=5/95 within 40 min; Detector, UV 254 nm)affording 430 mg (40%) of3-phenyl-N-[(1s,3s)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid. LCMS (ES, m/z): [M+H]⁺=351.2.

Step 2:3-Phenyl-N-[(1s,3s)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-phenyl-N-[(1s,3s)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak). To a 100-mL 3-necked round-bottom flask was placed asolution of3-phenyl-N-[(1s,3s)-3-[(3-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide(430 mg, 1.23 mmol, 1.00 equiv) in THF (30 mL), then the solution wascooled to 0° C. and MeMgBr (1.2 mL, 3 mol/L, 3.00 equiv) was addeddropwise with stirring at 0° C. over 5 min. The reaction was stirred for3 h at RT, then quenched by the addition of 2N HCl (10 mL) and 50 mL ofH₂O, and extracted with EtOAc (3×50 mL). The organic extracts werecombined, washed with brine (3×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (2:1). The pureisomers were separated by Chiral-Prep-HPLC (Prep-HPLC-009: Column,Phenomenex Lux 5 u Cellulose-3, 5*25 cm, 5 um; mobile phase, Hex and IPA(hold 50.0% IPA—in 17 min); Detector, UV 220/254 nm) affording 89.5 mg(20%) of3-phenyl-N-[(1s,3s)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) as a white solid and 65.5 mg (15%) of3-phenyl-N-[(1s,3s)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak) as a white solid.

3-Phenyl-N-[(1s,3s)-3-([3-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak): LCMS (ES, m/z): [M+H]⁺=367.1. ¹H NMR (300 MHz, DMSO-d₆) δ9.21-9.18 (d, J=7.5 Hz, 1H), 7.94-7.92 (m, 2H), 7.62 (s, 1H), 7.55-7.53(m, 4H), 6.15 (d, J=2.1 Hz, 1H), 4.94-4.92 (d, J=4.8 Hz, 1H), 4.71-4.63(m, 1H), 4.34-4.26 (m, 1H), 4.09-4.06 (d, J=6.9 Hz, 2H), 2.48-2.29 (m,3H), 1.98-1.89 (m, 2H), 1.34-1.32 (d, J=6.3 Hz, 3H). Purity (HPLC, 254nm): 98.2%.

3-Phenyl-N-[(1s,3s)-3-([3-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak): LCMS (ES, m/z): [M+H]⁺=367.2. ¹H NMR (300 MHz, DMSO-d₆) δ9.21-9.18 (d, J=7.5 Hz, 1H), 7.93-7.90 (m, 2H), 7.61 (s, 1H), 7.54-7.52(m, 4H), 6.14 (d, J=2.1 Hz, 1H), 4.94-4.93 (d, J=4.8 Hz, 1H), 4.70-4.62(m, 1H), 4.35-4.22 (m, 1H), 4.08-4.05 (d, J=6.9 Hz, 2H), 2.46-2.28 (m,3H), 1.97-1.88 (m, 2H), 1.33-1.31 (d, J=6.6 Hz, 3H). Purity (HPLC, 254nm): 97.9%.

Examples 67 and 683-Phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-Phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak)

Step 1:3-Phenyl-N-[(1r,3r)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 250-mL 3-necked round-bottom flask was placed a solution of(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid (2g, 6.99 mmol, 1.00 equiv) in THF (40 mL), then the solution was cooledto 0° C. and LiAlH₄ (800 mg, 21.08 mmol, 3.00 equiv) was added. Theresulting solution was stirred for 2 h at 5° C., then quenched by theaddition of Na₂SO₄.10H₂O. The solids were removed by filtration, thenthe filtrate was concentrated under reduced pressure affording 850 mg(45%) of3-phenyl-N-[(1r,3r)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow oil. LCMS (ES, m/z): [M+H]⁺=273.1.

Step 2: [(1r,3r)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate. To a 50-mL round-bottom flask was placed asolution of3-phenyl-N-[(1r,3r)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(850 mg, 3.12 mmol, 1.00 equiv) and DMAP (762 mg, 6.24 mmol, 1.20 equiv)in DCM (20 mL). To this solution was added TsCl (712 mg, 3.73 mmol, 1.20equiv) then the mixture was stirred for 24 h at RT. The reaction wasdiluted with 50 mL of water/ice and extracted with DCM. The organicextracts were combined, dried over anhydrous Na₂SO₄, and concentratedunder reduced pressure affording 980 mg (crude) of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate as a light yellow solid. LCMS (ES, m/z):[M+H]⁺=427.1.

Step 3:3-Phenyl-N-[(1r,3r)-3-[(4-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (980 mg, 2.30 mmol, 1.00 equiv) in DMF (20mL), then 1H-pyrazole-4-carbaldehyde (331 mg, 3.44 mmol, 1.50 equiv) andCs₂CO₃ (1.1 g, 3.37 mmol, 1.50 equiv) were added. The resulting solutionwas stirred for 3 h at 70° C., diluted with 50 mL of H₂O, filtered, andthen extracted with EtOAc. The organic extracts were combined, driedover anhydrous Na₂SO₄, and concentrated under reduced pressure. Theresidue was applied onto a silica gel column and eluted withEtOAc/petroleum ether (1:3) affording 400 mg (50%) of3-phenyl-N-[(1r,3r)-3-[(4-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=351.1.

Step 4:3-Phenyl-N-[(1r,3r)-3-[[4-(1-hydroxyethyl)-1H-pyrazol-1-yl]methyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 150-mL round-bottom flask was placed a solution of3-phenyl-N-[(1r,3r)-3-[(4-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide(600 mg, 1.71 mmol, 1.00 equiv) in THF (20 mL) then the solution wascooled to 5° C. To this solution was added MeMgBr (1M in hexane, 1.79mL, 1.79 mmol, 4.00 equiv) at 5° C. under nitrogen. The resultingsolution was stirred for 3 h at 5° C. The pH value of the solution wasadjusted to 3 with 1M HCl, then the resulting solution was extractedwith EtOAc. The organic extracts were combined, dried over anhydrousNa₂SO₄, and concentrated under reduced pressure. The residue was appliedonto a silica gel column and eluted with EtOAc/petroleum ether (1:3)affording 440 mg (70%) of3-phenyl-N-[(1r,3r)-3-[[4-(1-hydroxyethyl)-1H-pyrazol-1-yl]methyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid. LCMS (ES, m/z): [M+H]⁺=367.2.

Step 5:3-Phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak). The crudeN-(3-[[4-(1-hydroxyethyl)-1H-pyrazol-1-yl]methyl]cyclobutyl)-3-phenyl-1,2-oxazole-5-carboxamide(440 mg, 1.20 mmol, 1.00 equiv) was separated by Prep-SFC (Column:Phenomenex Lux 5 u Cellulose-4 £¬AXIA Packed, 250*21.2 mm, 5 um; MobilePhase A: CO2: 60, Mobile Phase B: Hex: 40; Flow rate: 40 mL/min; 220 nm;RT1:5.12; RT2:6.06) affording 141.7 mg (32%) of3-phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) as a white solid and 146.5 mg (33%) of3-phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak) as a red solid.

3-Phenyl-N-[(1r,3r)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak): LCMS (ES, m/z): [M+H−H₂O]⁺=349.1. ¹H NMR (300 MHz,DMSO-d₆): δ 9.26-9.23 (d, J=7.5 Hz, 1H), 7.93-7.90 (m, 2H), 7.62-7.60(m, 2H), 7.54-7.52 (m, 3H), 7.32 (s, 1H), 4.85-4.83 (d, J=4.8 Hz, 1H),4.71-4.63 (m, 1H), 4.55-4.47 (m, 1H), 4.20-4.17 (d, J=7.8 Hz, 2H),2.68-2.64 (m, 1H), 2.27-2.10 (m, 4H), 1.33-1.31 (d, J=6.3 Hz, 3H).Purity (HPLC, 254 nm): 98.2%.

3-Phenyl-N-[(1r,3r)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak): LCMS (ES, m/z): [M+H−H₂O]⁺=349.1. ¹H NMR (300 MHz,DMSO-d₆): δ 9.26-9.24 (d, J=7.2 Hz, 1H), 7.93-7.90 (m, 2H), 7.64-7.60(m, 2H), 7.54-7.52 (m, 3H), 7.32 (s, 1H), 4.85-4.84 (d, J=4.8 Hz, 1H),4.71-4.63 (m, 1H), 4.58-4.45 (m, 1H), 4.20-4.17 (d, J=7.8 Hz, 2H),2.68-2.64 (m, 1H), 2.27-2.10 (m, 4H), 1.33-1.31 (d, J=6.3 Hz, 3H).Purity (HPLC, 254 nm): 97.0%.

Examples 69 and 703-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak)

Step 1:3-Phenyl-N-[(1s,3s)-3-[(4-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of[(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (1 g, 2.34 mmol, 1.00 equiv) in DMF (15 mL)then Cs₂CO₃ (1.5 g, 4.60 mmol, 2.00 equiv) and1H-pyrazole-4-carbaldehyde (338 mg, 3.52 mmol, 1.50 equiv) were added.The resulting solution was stirred for 3 h at 100° C. then the solidswere removed by filtration. The crude product was purified byFlash-Prep-HPLC (CombiFlash-1: Column, C18 silica gel; mobile phase, X:H₂O (0.5% NH₄HCO₃), Y: ACN, X/Y=90/10 increasing to X/Y=5/95 within 40min; Detector, UV 254 nm) affording 460 mg (56%) of3-phenyl-N-[(1s,3s)-3-[(4-formyl-1H-pyrazol-1-yl)methyl]cyclobutyl]-1,2-oxazole-5-carboxamideas a yellow solid. LCMS (ES, m/z): [M+H]⁺=351.1.

Step 2:3-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak) and3-phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak). To a 100-mL 3-necked round-bottom flask was placed asolution of3-phenyl-N-[(1s,3s)-3-[(4-formyl-1H-pyrazol-1-yl]methyl]cyclobutyl]-1,2-oxazole-5-carboxamide(460 mg, 1.31 mmol, 1.00 equiv) in THF (30 mL) then the solution wascooled to 0° C. To this solution was added MeMgBr (1.3 mL, 3.00 equiv)dropwise with stirring at 0° C. over 10 min The resulting solution wasstirred for 3 h at RT, quenched with 2N HCl (10 mL) and 50 mL of H₂O,and extracted with EtOAc (3×50 mL). The organic extracts were combined,washed with brine (3×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (2:1). Theproduct was purified by Chiral-Prep-HPLC (Prep-HPLC-004: Column,Chiralpak IB, 2*25 cm, 5 um; mobile phase, Hex and ethanol (hold 10.0%ethanol in 41 min); Detector, uv 254/220 nm) affording 132.3 mg (28%) of3-phenyl-N-[(1s,3s)-3([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide front peak) as anoff-white solid and 139.4 mg (29%) of3-phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak) as an off-white solid.

3-Phenyl-N-[(1s,3s)-3-([4-[(1R)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(front peak): LCMS (ES, m/z): [M+H]⁺=367.1. ¹H NMR (300 MHz, DMSO-d₆) δ9.21-9.18 (d, J=7.5 Hz, 1H), 7.94-7.91 (m, 2H), 7.62 (s, 1H), 7.55-7.51(m, 3H), 7.48 (s, 1H), 7.32 (s, 1H), 4.85 (brs, 1H), 4.70-4.64 (q, J=6.6Hz, 1H), 4.36-4.23 (m, 1H), 4.10-4.07 (d, J=6.9 Hz, 2H), 2.46-2.29 (m,3H), 1.99-1.89 (m, 2H), 1.33-1.31 (d, J=6.3 Hz, 3H). Purity (HPLC, 254nm): 96.4%.

3-Phenyl-N-[(1s,3s)-3-([4-[(1S)-1-hydroxyethyl]-1H-pyrazol-1-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide(second peak): LCMS (ES, m/z): [M+H]⁺=367.1. ¹H NMR (300 MHz, DMSO-d₆) δ9.21-9.18 (d, J=7.5 Hz, 1H), 7.92-7.87 (m, 2H), 7.68 (s, 1H), 7.61-7.48(m, 4H), 7.31 (s, 1H), 4.85 (brs, 1H), 4.73-4.65 (m, 1H), 4.36-4.28 (m,1H), 4.09-4.07 (d, J=6.6 Hz, 2H), 2.43-2.32 (m, 3H), 1.95-1.85 (m, 2H),1.32-1.31 (d, J=5.1 Hz, 3H). Purity (HPLC, 254 nm): 96.0%.

Example 713-Phenyl-N-[(1r,3r)-3-(4-fluorophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide

To a 50-mL round-bottom flask was placed a solution of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (550 mg, 1.29 mmol, 1.00 equiv) in DMF (10mL), then 4-fluorophenol (217 mg, 1.94 mmol, 1.50 equiv) and Cs₂CO₃ (631mg, 1.93 mmol, 1.50 equiv) were added. The resulting solution wasstirred for 3 h at 70° C., then diluted with H₂O, and extracted withEtOAc. The organic extracts were combined, dried over anhydrous Na₂SO₄,and concentrated under reduced pressure. The residue was applied onto asilica gel column and eluted with EtOAc/petroleum ether (1:4). Theresulting crude product was further purified by Prep-HPLC (Waters:Column, X Bridge Shield RP18 OBD Column, 5 um, 19*150 mm; mobile phase,water with 0.03% TFA and CH₃CN (10.0% CH₃CN up to 30% CH₃CN in 8 min, upto 100% in 4 min and down to 10% in 3 min); Detector, uv 254 nm and 220nm) affording 152.3 mg (53%) of3-phenyl-N-[(1r,3r)-3-(4-fluorophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=367.1. ¹H NMR (300 MHz,DMSO-d₆): δ 9.31-9.29 (d, J=7.2 Hz, 1H), 7.92-7.91 (m, 2H), 7.63 (s,1H), 7.55-7.54 (m, 3H), 7.15-7.09 (m, 2H), 6.99-6.95 (m, 2H), 4.61-4.53(m, 1H), 4.05-4.03 (d, J=6.9 Hz, 2H), 2.69-2.63 (m, 1H), 2.38-2.29 (m,2H), 2.23-2.17 (m, 2H). Purity (HPLC, 254 nm): 97.4%.

Example 723-phenyl-N-[(1s,3s)-3-(4-fluorophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide

To a 25-mL round-bottom flask was placed a solution of[(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (213 mg, 0.50 mmol, 1.00 equiv) in DMF (5mL), then Cs₂CO₃ (326 mg, 1.00 mmol, 2.00 equiv) and 4-fluorophenol (84mg, 0.75 mmol, 1.50 equiv) were added. The resulting solution wasstirred for 3 h at 100° C., then diluted with 50 mL of H₂O, andextracted with EtOAc (2×50 mL). The organic extracts were combined,washed with brine (2×50 mL), dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The crude product was purified byPrep-TLC (petroleum ether/ethyl acetate=1:2) affording 56.9 mg (31%) of3-phenyl-N-([1s,3s)-3-(4-fluorophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=367.1. ¹H NMR (300 MHz,DMSO-d₆) δ 9.23-9.21 (d, J=7.5 Hz, 1H), 7.94-7.90 (m, 2H), 7.62 (s, 1H),7.55-7.48 (m, 3H), 7.14-7.07 (m, 2H), 6.97-6.93 (m, 2H), 4.40-4.32 (m,1H), 3.94-3.92 (d, J=5.1 Hz, 2H), 2.43-2.39 (m, 3H), 2.00-1.94 (m, 2H).Purity (HPLC, 254 nm): 99.5%.

Example 733-phenyl-N-[(1r,3r)-3-(4-cyanophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide

To a 50-mL round-bottom flask was placed a solution of[(1r,3r)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutyl]methyl4-methylbenzene-1-sulfonate (560 mg, 1.31 mmol, 1.00 equiv) in DMF (10mL), then 4-hydroxybenzonitrile (235 mg, 1.97 mmol, 1.50 equiv) andCs₂CO₃ (643 mg, 1.97 mmol, 1.50 equiv) were added. The resultingsolution was stirred for 2 h at 110° C., then diluted by the addition ofwater, and extracted with EtOAc. The organic extracts were combined, waswashed with H₂O, dried over anhydrous Na₂SO₄, and concentrated underreduced pressure. This residue was purified by Prep-HPLC (Waters:Column, X Bridge Prep C18 5 um, 19*150 mm; mobile phase, water with0.03% TFA and CH₃CN (10.0% CH₃CN up to 30% CH₃CN in 6 min, up to 100% in5 min and down to 10% in 2 min); Detector, uv 254 nm and 220 nm)affording 129.9 mg (87%) of3-phenyl-N-[(1r,3r)-3-(4-cyanophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=374.1. ¹H NMR (300 MHz,DMSO-d₆): δ 9.32-9.30 (d, J=7.5 Hz, 1H), 7.94-7.91(m, 2H), 7.78-7.76 (d,J=8.7 Hz, 2H), 7.63 (s, 1H), 7.55-7.54 (m, 3H), 7.15-7.12 (m, J=8.7 Hz,2H), 4.63-4.55 (m, 1H), 4.19-4.17 (d, J=6.9 Hz, 2H), 2.72-2.66 (m, 1H) ,2.40-2.30 (m, 2H), 2.24-2.18 (m, 2H). Purity (HPLC, 254 nm): 97.3%.

Example 743-Phenyl-N-[(1s,3s)-3-(4-cyanophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: tert-Butyl(1s,3s)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate. To a100-mL round-bottom flask was placed a solution of tert-butyl(1s,3s)-3-aminocyclobutane-1-carboxylate (1.7 g, 9.93 mmol, 1.00 equiv)in DCM (50 mL), then 3-phenyl-1,2-oxazole-5-carboxylic acid (1.9 g,10.04 mmol, 1.00 equiv), HATU (5.7 g, 14.99 mmol, 1.50 equiv) and DIEA(3.9 g, 30.18 mmol, 3.00 equiv) were added. The resulting solution wasstirred for 1 h at RT, then quenched by the addition of water, andextracted with EtOAc. The organic extracts were combined, washed withbrine, dried over anhydrous Na₂SO₄, and concentrated under reducedpressure. The residue was applied onto a silica gel column and elutedwith EtOAc/petroleum ether (1:7) affording 2 g (59%) of tert-butyl(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate as awhite solid. LCMS (ES, m/z): [M+Na]⁺=365.1.

Step 2: (1s,3s)-3-(3-Phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylicacid. To a 100-mL round-bottom flask was placed a solution of tert-butyl(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylate (2 g,5.84 mmol, 1.00 equiv) in DCM (20 mL) and TFA (7 mL). The resultingsolution was stirred for 4 h at RT, then the solvent was removed underreduced pressure affording 1.8 g (crude) of(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid asan off-white solid. LCMS (ES, m/z): [M+H]⁺=286.8.

Step 3:3-Phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 100-mL round-bottom flask was placed a solution of(1s,3s)-3-(3-phenyl-1,2-oxazole-5-amido)cyclobutane-1-carboxylic acid (1g, 2.79 mmol, 1.00 equiv, 80%) in THF (25 mL), then the solution wascooled to 0° C. To this solution was added LiAlH₄ (425 mg, 11.18 mmol,4.00 equiv) in portions at 0° C., then the resulting solution wasstirred for 1 h at 10° C. The reaction was quenched by the addition ofNa₂SO₄.10H₂O, then the solids were removed by filtration, and thefiltrate was concentrated under reduced pressure. The residue wasapplied onto a silica gel column and eluted with EtOAc/petroleum ether(1:2) affording 420 mg (55%) of3-phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z): [M+H]⁺=273.1.

Step 4:3-Phenyl-N-[(1s,3s)-3-(4-cyanophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 100-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of3-phenyl-N-[(1s,3s)-3-(hydroxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamide(420 mg, 1.31 mmol, 1.00 equiv, 85%), 4-hydroxybenzonitrile (320 mg,2.69 mmol, 2.00 equiv) and PPh₃ (1.08 g, 4.12 mmol, 3.00 equiv) in THF(10 mL). This was followed by the addition of DIAD (840 mg, 4.15 mmol,3.00 equiv) dropwise with stirring at 0° C. The resulting solution wasstirred for 2 h at RT. The reaction was quenched by the addition ofwater, then extracted with EtOAc. The organic extracts were combined,washed with brine, dried over anhydrous Na₂SO₄, and concentrated underreduced pressure. The crude product was purified by Flash-Prep-HPLC(IntelFlash-1: Column, C18; mobile phase, MeCN/H₂O=5:95 increasing toMeCN/H₂O=50:50 within 20 min; Detector, UV 254 nm) affording 148.5 mg(30%) of3-phenyl-N-[(1s,3s)-3-(4-cyanophenoxymethyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid. LCMS (ES, m/z):[M+H]⁺=374.2. ¹H NMR (400 MHz,DMSO-d₆): δ 9.25-9.24 (d, J=7.6 Hz, 1H), 7.94-7.92 (m, 2H), 7.79-7.76(m, 2H), 7.64 (s, 1H), 7.55-7.53 (m, 3H), 7.16-7.12 (m, 2H), 4.43-4.35(p, J=8.0 Hz, 1H), 4.08-4.06 (d, J=6.0 Hz, 2H), 2.45-2.40 (m, 3H),2.02-1.97 (m, 2H). Purity (HPLC, 254 nm): 98.2%.

Example 75 and 763-(5-Fluorothiophen-2-yl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-(5-Fluorothiophen-2-yl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide

Step 1: 5-Fluoro-N-methoxy-N-methylthiophene-2-carboxamide. To a 100-mLround-bottom flask was placed a solution of5-fluorothiophene-2-carboxylic acid (1 g, 6.84 mmol, 1.00 equiv) in DCM(50 mL), then methoxy(methyl)amine hydrochloride (730 mg, 7.53 mmol,1.10 equiv), HATU (3.9 g, 10.26 mmol, 1.50 equiv), and DIEA (2.82 mL,3.00 equiv) were added. The reaction was stirred for 3 h at roomtemperature, diluted with H₂O, and extracted with DCM (2×100 mL). Theorganic extracts were combined, washed with brine (2×50 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure. The residuewas applied onto a silica gel column and eluted with EtOAc/petroleumether (1:4) affording 1.14 g (88%) of5-fluoro-N-methoxy-N-methylthiophene-2-carboxamide as a yellow liquid.LCMS (ES, m/z): [M+H]⁺=190.0.

Step 2: (E)-N-[(5-Fluorothiophen-2-yl)methylidene]hydroxylamine. To a50-mL round-bottom flask was placed a solution of5-fluoro-N-methoxy-N-methylthiophene-2-carboxamide (1.14 g, 6.03 mmol,1.00 equiv) in THF (20 mL), then LiAlH₄ (342 mg, 9.01 mmol, 1.20 equiv)was added. The action was stirred for 1 h at room temperature, thenquenched by the addition of 20 mL of H₂O/ice, and extracted with EtOAc(2×20 mL). The organic extracts were dried and used directly in the nextstep.

To a 250-mL round-bottom flask was placed a solution of5-fluorothiophene-2-carbaldehyde (780 mg, 5.99 mmol, 1.00 equiv) inEtOH/EtOAc (120 mL), then NH₂OH.HCl (0.5 g, 1.20 equiv) was added. Theresulting solution was stirred for 3 h at room temperature then thesolvent was removed under reduced pressure. The residue was dissolved inH₂O (50 mL), then the resulting solution was extracted with EtOAc (3×100mL). The organic extracts were combined, washed with brine (2×100 mL),dried over anhydrous Na₂SO₄, and concentrated under reduced pressureaffording 650 mg (75%) of(E)-N-[(5-fluorothiophen-2-yl)methylidene]hydroxylamine as a yellowsolid. LCMS (ES, m/z): [M+H]⁺=146.0.

Step 3: Methyl 3-(5-Fluorothiophen-2-yl)-1,2-oxazole-5-carboxylate. To a25-mL round-bottom flask was placed a solution of(E)-N-[(5-fluorothiophen-2-yl)methylidene]hydroxylamine (300 mg, 2.07mmol, 1.00 equiv) DMF (5 mL), then NCS (414 mg, 3.11 mmol, 1.50 equiv)was added in small portions. The resulting solution was stirred for 1 hat room temperature, then methyl prop-2-ynoate (0.27 mL, 2.00 equiv) wasadded followed by Na₂CO₃ (260 mg, 3.09 mmol, 1.50 equiv) in smallportions. The reaction was stirred for 2 h at room temperature, dilutedwith 50 mL of H₂O, and extracted with EtOAc (3×100 mL). The organicextracts were combined, washed with brine (2×50 mL), dried overanhydrous Na₂SO₄, and concentrated under vacuum. The residue waspurified by prep TLC (ethyl acetate/petroleum ether=⅓) affording 200 mg(43%) of methyl 3-(5-fluorothiophen-2-yl)-1,2-oxazole-5-carboxylate as ayellow solid.

Step 4: 3-(5-fluorothiophen-2-yl)-1,2-oxazole-5-carboxylic acid. To a50-mL round-bottom flask was placed a solution of methyl3-(5-fluorothiophen-2-yl)-1,2-oxazole-5-carboxylate (254 mg, 1.12 mmol,1.00 equiv) in THF-H₂O (3:1, 10 mL), then LiOH (52 mg, 2.17 mmol, 2.00equiv) was added. The reaction was stirred for 1 h at room temperature,diluted with H₂O (20 mL), and washed with ethyl acetate (2×50 mL). ThepH of the aqueous layer was adjusted to 3 with 1M HCl, then theresulting solution was extracted with EtOAc (3×50 mL). The organicextracts were combined, was washed with brine (2×50 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure affording 170mg (71%) of 3-(5-fluorothiophen-2-yl)-1,2-oxazole-5-carboxylic acid as ayellow solid. LCMS (ES, m/z): [M+H]⁺=214.1.

Step 5:3-(5-Fluorothiophen-2-yl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideand3-(5-Fluorothiophen-2-yl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide.To a 50-mL round-bottom flask was placed a solution of3-(5-fluorothiophen-2-yl)-1,2-oxazole-5-carboxylic acid (170 mg, 0.80mmol, 1.00 equiv) in DCM (20 mL), then3-([5-[(1R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutan-1-amine(273 mg, 0.88 mmol, 1.10 equiv), HATU (455 mg, 1.20 mmol, 1.50 equiv),and DIEA (0.33 mL, 3.00 equiv) were added. The reaction was stirred for3 h at room temperature, diluted with H₂O, and extracted with DCM. Theorganic extracts were combined, washed with brine (2×30 mL), dried overanhydrous Na₂SO₄, and concentrated under reduced pressure. The residuewas purified by Prep-TLC (EtOAc/petroleum ether=¼), then the resultingpure isomers were separated by Chiral-Prep-HPLC (Prep-HPLC-032: Column,Lux 5 u Cellulose-4,AXIA Packed, 250*21.2 mm; mobile phase, Hex and IPA(hold 30.0% IPA in 21 min); Detector, UV 254/220 nm) affording 37.2 mg(19%) of3-(5-fluorothiophen-2-yl)-N-[(1s,3s)-3-([5-([1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid and 9.4 mg (5%) of3-(5-fluorothiophen-2-yl)-N-[(1r,3r)-3-([5-([1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamideas a white solid.

3-(5-Fluorothiophen-2-yl)-N-[(1s,3s)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=393.1. ¹H NMR (300 MHz, DMSO-d₆): δ 9.23-9.20 (d,J=7.8 Hz, 1H), 7.61 (s, 1H), 7.57-7.55 (t, J=3.9 Hz, 2H), 6.94-6.92 (m,1H), 5.91-5.89 (d, J=5.7 Hz, 1H), 4.92-4.83 (m, 1H), 4.33-4.23 (m, 1H),2.97-2.95 (d, J=6.3 Hz, 2H), 2.46-2.33 (m, 3H), 1.96-1.90 (m, 2H),1.45-1.43 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm): 98.8%.

3-(5-Fluorothiophen-2-yl)-N-[(1r,3r)-3-([5-[(1R)-1-hydroxyethyl]-1,3,4-oxadiazol-2-yl]methyl)cyclobutyl]-1,2-oxazole-5-carboxamide:LCMS (ES, m/z): [M+H]⁺=393.1. ¹H NMR (300 MHz, DMSO-d₆): δ 9.33-9.31 (d,J=7.2 Hz, 1H), 7.62 (s, 1H), 7.57-7.54 (t, J=4.2 Hz, 1H), 6.94-6.92 (m,1H), 5.92-5.90 (d, J=5.7 Hz, 1H), 4.92-4.84 (m, 1H), 4.57-4.49 (m, 1H),3.09-3.06 (d, J=7.8 Hz, 2H), 2.72-2.64 (m, 1H), 2.37-2.27 (m, 2H),2.17-2.12 (m, 2H), 1.46-1.43 (d, J=6.6 Hz, 3H). Purity (HPLC, 254 nm):99.3%.

Example 77 CFTR Activity Assays

i. Ussing Measurements

As discussed above, Ussing measurements can be used to measure CFTRactivity. In this example, primary lung epithelial cells (hBEs)homozygous for the Cystic Fibrosis-causing ΔF508 mutation weredifferentiated for a minimum of 4 weeks in an air-liquid interface onSnapWell filter plates prior to the Ussing measurements. Cells wereapically mucus-washed for 30 minutes prior to treatment with compounds.The basolateral media was removed and replaced with media containing thecompound of interest diluted to its final concentration from DMSOstocks. Treated cells were incubated at 37° C. and 5% CO₂for 24 hours.At the end of the treatment period, the cells on filters weretransferred to the Ussing chamber and equilibrated for 30 minutes. Theshort-circuit current was measured in voltage clamp-mode (V_(hold)=0mV), and the entire assay was conducted at a temperature of 36° C.-36.5°C. Once the voltages stabilized, the chambers were clamped, and data wasrecorded by pulse readings every 5 seconds. Following baseline currentstabilization, the following additions were applied and the changes incurrent and resistance of the cells was monitored:

-   -   1. Benzamil to the apical chamber to inhibit ENaC sodium channel    -   2. Forskolin to both chambers to activate ΔF508-CFTR by        phosphorylation.    -   3. Genistein or VX-770 (ivacaftor) to both chambers to        potentiate ΔF508-CFTR channel opening.    -   4. CFTRinh-172 to the apical chamber to inhibit ΔF508-CFTR Cl—        conductance.

The inhibitable current (that current that is blocked by CFTRinh-172) ismeasured as the specific activity of the ΔF508-CFTR channel, andincreases in response to compound in this activity over that observed invehicle-treated samples are identified as the correction of ΔF508-CFTRfunction imparted by the compound tested.

ii. hBE Equivalent Current (Ieq) Assay

Primary lung epithelial cells homozygous for the Cystic Fibrosis-causingΔF508 mutation were differentiated for a minimum of 4 weeks in anair-liquid interface on Costar 24 well HTS filter plates prior to theequivalent current (Ieq) measurements. Cells were apically mucus-washedfor 30 minutes 24 h prior to treatment with compounds. The basolateralmedia was removed and replaced with media containing the compound ofinterest diluted to its final concentration from DMSO stocks. Treatedcells were incubated at 37° C. and 5% CO₂for 24 hours. At the end of thetreatment period, the media was changed to the Ieq experimental solutionfor 30 minutes before the experiment and plates are maintained in aCO₂-free incubator during this period. The plates containing the cellswere then placed in pre-warmed heating blocks at 36° C.±0.5 for 15minutes before measurements are taken. The transepithelial voltage(V_(T)) and conductance (G_(T)) were measured using a custom 24 channelcurrent clamp (TECC-24) with 24 well electrode manifold. The Ieq assaymeasurements were made following additions with standardized timeperiods:

-   -   1. The baseline V_(T) and G_(T) values were measured for        approximately 20 minutes.    -   2. Benzamil was added to block ENaC for 15 minutes.    -   3. Forskolin plus VX-770 (ivacaftor) were added to maximally        activate ΔF508-CFTR for 27 minutes.    -   4. Bumetanide was added to inhibit the NaK₂Cl cotransporter and        shut-off secretion of chloride.

The activity data captured was the area under the curve (AUC) for thetraces of the equivalent chloride current. The AUC was collected fromthe time of the forskolin/VX-770 addition until the inhibition bybumetanide addition. Correction in response to compound treatment wasscored as the increase in the AUC for compound-treated samples over thatof vehicle-treated samples.

The results are shown below in Table 2. ++ indicates activity ≥25% runat 10 uM of VX-809 at 1 uM, + indicates activity 10 to <25% run at 10 uMof VX-809 at 1 uM, ** indicates activity ≥200% of VX-809 (1 uM) withcompound at 10 uM and VX-809 at 1 uM; * indicates activity 100-200% ofVX-809(1 uM) with compound at 10 uM and VX-809 at 1 uM. ## indicatesactivity ≥200% of VX-809 (3 uM) with compound at 10 uM and VX-809 at 3uM; ≐ indicates activity 100-200% of VX-809(3 uM) with compound at 10 uMand VX-809 at 3 uM.

TABLE 2 # Structure Ieq Ussing 1

++ 2

++ 3

++ 4

+ 5

## 6

* ## 7

++, * 8

+ 9

++ 10

+ 11

++ 12

++, * 13

14

* 15

* 16

17

* 18

19

20

* 21

* 22

* 23

* 24

* 25

* 26

27

* 28

** 29

** 30

* 31

32

33

34

35

* 36

* 37

** 38

** 39

40

** 41

** 42

* 43

** 44

** 45

* 46

* 47

* 48

49

50

* 51

52

53

54

55

56

57

** 58

* 59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

Example 78

i. Ussing Measurements

As discussed above, Ussing measurements were used to measure CFTRactivity. In this method, primary lung epithelial cells (hBEs) with aCystic fibrosis causing class I mutation were differentiated for aminimum of 4 weeks in an air-liquid interface on SnapWell™ filter platesprior to the Ussing measurements. Cells were apically mucus-washed for30 minutes prior to treatment with compounds. The basolateral media wasremoved and replaced with media containing the compound of interestdiluted to its final concentration from DMSO or aqueous stocks. Treatedcells were incubated at 37° C. and 5% CO₂for 24 hours. At the end of thetreatment period, the cells on filters were transferred to the Ussingchamber and equilibrated for 30 minutes. The short-circuit current wasmeasured in voltage clamp-mode (V_(hold)=0 mV), and the entire assay wasconducted at a temperature of 36° C.-36.5° C. Once the voltagesstabilized, the chambers were clamped, and data were recorded by pulsereadings every 5 seconds. Following baseline current stabilization, thefollowing additions were applied and the changes in current andresistance of the cells were monitored:

-   -   1. Benzamil to the apical chamber to inhibit ENaC sodium        channel.    -   2. Forskolin to both chambers to activate ΔF508-CFTR by        phosphorylation.    -   3. Ivacaftor or Genistein to the apical chamber to potentiate        ΔF508-CFTR channel opening.    -   4. CFTRinh-172 to the apical chamber to inhibit ΔF508-CFTR Cl—        conductance.

The forskolin-sensitive current and inhibitable current (thatpotentiated current that was blocked by CFTRinh-172) were measured asthe specific activity of the ΔF508-CFTR channel, and increase inresponse to compound in this activity over that observed invehicle-treated samples were identified as the correction of ΔF508-CFTRfunction imparted by the compound tested.

The results are shown below in Tables 3 and 4. Compound A is 10 uM andVX-809 is 3 uM and ivacaftor is 1 uM.

TABLE 3 Activity in F508/F508del HBEs (relative to VX-809 and ivacaftoractivity) VX-809 + ivacaftor 100% Compound A + VX-809 + ivacaftor 242%

TABLE 4 Activity in G542X/F508del HBEs (relative to VX-809 and ivacaftoractivity) VX-809 + ivacaftor 100% Compound A + VX-809 + ivacaftor 190%

Example 79

i. Ussing Measurements

As discussed above, Ussing measurements was used to measure CFTRactivity. In this method, primary lung epithelial cells (hBEs) with aCystic Fibrosis-causing class III mutation were differentiated for aminimum of 4 weeks in an air-liquid interface on SnapWell™ filter platesprior to the Ussing measurements. Cells were apically mucus-washed for30 minutes prior to treatment with compounds. The basolateral media wasremoved and replaced with media containing the compound of interestdiluted to its final concentration from DMSO stocks. Treated cells wereincubated at 37° C. and 5% CO₂ for 24 hours. At the end of the treatmentperiod, the cells on filters were transferred to the Ussing chamber andequilibrated for 30 minutes. The short-circuit current was measured involtage clamp-mode (V_(hold)=0 mV), and the entire assay was conductedat a temperature of 36° C.-36.5° C. Once the voltages stabilized, thechambers were clamped, and data was recorded by pulse readings every 5seconds. Following baseline current stabilization, the followingadditions were applied and the changes in current and resistance of thecells was monitored:

-   -   1. Benzamil to the apical chamber to inhibit ENaC sodium        channel.    -   2. Forskolin to both chambers to activate ΔF508-CFTR by        phosphorylation.    -   3. Ivacaftor or Genistein to the apical chamber to potentiate        ΔF508-CFTR channel opening.    -   4. CFTRinh-172 to the apical chamber to inhibit ΔF508-CFTR Cl—        conductance.

The forskolin-sensitive current and inhibitable current (thatpotentiated current that is blocked by CFTRinh-172) were measured as thespecific activity of the ΔF508-CFTR channel, and increase in response tocompound in this activity over that observed in vehicle-treated sampleswere identified as the correction of ΔF508-CFTR function imparted by thecompound tested.

The results are shown below in Tables 5 and 6. Compound A is 10 uM andVX-809 is 3 uM and ivacaftor is 1 uM.

TABLE 5 Activity in R117H/F508del HBEs (relative to ivacaftor activity)ivacaftor 100% Compound A + ivacaftor 193%

TABLE 6 Activity in G551D/F508del HBEs (relative to ivacaftor activity)ivacaftor 100% Compound A + ivacaftor 160%

Combination Combination Relative Combination with with Activity of Standwith ivacaftor and ivacaftor and Combination Genotype 100% Aloneivacaftor lumacaftor VX-661 with NB124 G542X/G542X NB124 ++ ++++G542X/F508del ivacaftor and + ++++ lumacaftor F508del/F508del ivacaftorand + ++++ lumacaftor F508del/F508del ivacaftor ++++ and VX-661G551D/F508del ivacaftor + ++++ R117H/F508del ivacaftor +++ ++++ 3849 +10 kb ivacaftor ++ +++ C > T/N1303K Table 7 indicates mutation type andactivity with compounds/combination with compound A. ## indicatesactivity at 30 uM of 50% to <100% of the indicated relative activitytreatment, #### indicates activity at 30 uM of ≥150% of the indicatedrelative activity treatment, + indicates activity at 10 uM of 15% to<50% of the indicated relative activity treatment, ++ indicates activityat 10 uM of 50% to <100% of the indicated relative activity treatment,+++ indicates activity at 10 uM of 100% to <150% of the indicatedrelative activity treatment, ++++ indicates activity at 10 uM of ≥150%of the indicated relative activity treatment. NB124 is used at 250ug/ml, ivacaftor is used at 1 uM, lumacaftor is used at 3 uM, and VX-661is used at 3 uM.

While this disclosure has been particularly shown and described withreferences to certain embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the disclosureencompassed by the appended claims.

INCORPORATION BY REFERENCE

All publications and patents mentioned herein, including those itemslisted below, are hereby incorporated by reference in their entirety forall purposes as if each individual publication or patent wasspecifically and individually incorporated by reference. In case ofconflict, the present application, including any definitions herein,will control.

EQUIVALENTS

While specific embodiments of the subject disclosure have beendiscussed, the above specification is illustrative and not restrictive.Many variations of the disclosure will become apparent to those skilledin the art upon review of this specification. The full scope of thedisclosure should be determined by reference to the claims, along withtheir full scope of equivalents, and the specification, along with suchvariations.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in this specification and attached claimsare approximations that may vary depending upon the desired propertiessought to be obtained by the present disclosure.

What is claimed is:
 1. A method of treating cystic fibrosis in a patientin need thereof, comprising administering to the patient apharmaceutically effective amount of a compound represented by formulaI:

or a pharmaceutically acceptable salt or stereoisomer thereof, wherein:X₁ is N; pp is 1, 2, or 3; R₁₁ is independently selected for eachoccurrence from the group consisting of hydrogen, halogen, and C₁₋₄alkyl (optionally substituted by one, two or three halogens); R₃₁ isselected from the group consisting of hydrogen, fluorine, and C₁₋₄alkyl; L₁ is selected from the group consisting of C₃₋₅ cycloalkylene,C₁₋₃ alkylene-NR_(hh)—S(O)_(W)—, —C₁₋₃ alkylene-S(O)_(W)—NR_(hh)—, C₃₋₆cycloalkylene-C₀₋₂ alkylene-S(O)_(W)—NR_(hh), and C₃₋₆ cycloalkylene-C₀₋₂ alkylene NR_(hh)—S(O)_(W)—, wherein L₁ may be optionallysubstituted by one, two or three substituents selected from the groupconsisting of halogen, hydroxyl, and C₁₋₃ alkyl (optionally substitutedby one, two or three substituents each selected independently fromR_(ff)); R₄₄ is selected from the group consisting of halogen, hydroxyl,C₁₋₃ alkoxy, phenyl, —O—phenyl, —NR′-phenyl, heterocycle, and a 5-6membered monocyclic or 8-10 membered bicyclic heteroaryl having one, twoor three heteroatoms each selected from O, N, and S; wherein phenyl,—O—phenyl, —NR′-phenyl, heterocycle and heteroaryl may be optionallysubstituted by one or two substituents each selected independently fromR_(gg); R_(ff) is selected for each occurrence from the group consistingof halogen, hydroxyl, C₁₋₄ alkyl, C₁₋₄ alkoxy, C₂₋₄ alkenyl, C₃₋₆cycloalkyl, —NR′R″, —NR′—S(O)_(W)—C₁₋₃ alkyl, S(O)_(w)—NR′R″, and—S(O)_(w)—C₁₋₃ alkyl, where w is 0, 1, or 2, wherein C₁₋₄ alkyl, C₁₋₄alkoxy, C₂₋₄ alkenyl and C₃₋₆ cycloalkyl may be optionally substitutedby one, two or three substituents each independently selected from thegroup consisting of halogen, hydroxyl, —NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl,S(O)_(w)—NR′R″, and —S(O)_(W)—C₁₋₃ alkyl; R_(gg) is selected for eachoccurrence from the group consisting of halogen, hydroxyl, cyano,—NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl, —S(O)_(W)—NR′R″, and —S(O)_(W)—C₁₋₃alkyl, where w is 0, 1, or 2; heterocycle, C₁₋₆ alkyl, C₃₋₆ cycloalkyl,and C₁₋₆ alkenyl, wherein C₁₋₆ alkyl, C₃₋₆ cycloalkyl, and C₁₋₆ alkenylare optionally substituted by one, two, or three substituents eachindependently selected from R_(jj); and heterocycle is optionallysubstituted by one, two, or three substituents each independentlyselected from R₁₁; R_(jj) is selected for each occurrence from the groupconsisting of halogen, hydroxyl, C₁₋₆ alkoxy (optionally substituted byone, two, or three substituents each independently selected fromR_(kk)); C₃₋₆ cycloalkyl, C₃₋₆ cycloalkoxy, heterocycle, C(O)OH,—C(O)OC₁₋₆ alkyl, —NR′R″, —NR′—S(O)_(w)—C₁₋₃ alkyl, —S(O)_(W)—NR′R″, and—S(O)_(W)—C₁₋₃ alkyl, where w is 0, 1, or 2; R_(kk) is selected for eachoccurrence from the group consisting of halogen, hydroxyl, C₁₋₆ alkyl(optionally substituted by one, two, or three substituents eachindependently selected from halogen, hydroxyl, C₃₋₆ cycloalkyl, andheterocycle (optionally substituted by C₁₋₆ alkyl)), C₃₋₆ cycloalkyl(optionally substituted by one, two, or three substituents eachindependently selected from halogen, hydroxyl, and C₁₋₆ alkyl), phenyl,heterocycle (optionally substituted by one, two or three substituentsindependently selected from halogen, hydroxyl, and C₁₋₆ alkyl), andheteroaryl; R_(ll) is selected for each occurrence from the groupconsisting of halogen, hydroxyl, C₁₋₆ alkyl (optionally substituted byone, two, or three substituents each independently selected fromhalogen, hydroxyl, and C₃₋₆ cycloalkyl) and heterocycle (optionallysubstituted by one, two or three substituents independently selectedfrom halogen, hydroxyl, and C₁₋₆ alkyl); R′ and R″ are eachindependently selected for each occurrence from H, C₁₋₄ alkyl, phenyland heterocycle; w is 0, 1 or 2; R_(hh) is selected for each occurrencefrom the group consisting of H, C₁₋₆ alkyl and C₃₋₆ cycloalkyl; andadministering to said patient a) cystic fibrosis transmembraneconductance regulator (CFTR) potentiator and/or b) a CFTR corrector. 2.The method of claim 1, wherein L₁ is C₃₋₅ cycloalkylene.
 3. The methodof claim 1, wherein R₃₁ is selected from the group consisting of H andF.
 4. The method of claim 1, wherein the compound is represented by:


5. The method of claim 1, wherein R₄₄ is selected from the groupconsisting of: pyrrolidinyl, piperidinyl, tetrahydropyranyl, andtetrahydofuranyl.
 6. The method of claim 1, wherein R₄₄ is selected fromthe group consisting of

wherein X₂ is selected from the group consisting of O, S and NR_(hh);and each R₆₆, R₇₇ and R₈₈ is independently selected from R_(gg).
 7. Themethod of claim 6, where each R₆₆, R₇₇ and R₈₈ is selected from thegroup consisting of H, halogen, methyl (optionally substituted by one,two or three substituents each selected from halogen, hydroxyl, methoxyand ethoxy), ethyl (optionally substituted by one, two or threesubstituents each selected from halogen, hydroxyl, methoxy and ethoxy),propyl (optionally substituted by one, two or three substituents eachselected from halogen, hydroxyl, methoxy and ethoxy), isopropyl(optionally substituted by one, two or three substituents each selectedfrom halogen, hydroxyl, methoxy and ethoxy), n-butyl (optionallysubstituted by one, two or three substituents each selected fromhalogen, hydroxyl, methoxy and ethoxy), t-butyl (optionally substitutedby one, two or three substituents each selected from halogen, hydroxyl,methoxy and ethoxy), s-butyl (optionally substituted by one, two orthree substituents each selected from halogen, hydroxyl, methoxy andethoxy) and isobutyl (optionally substituted by one, two or threesubstituents each selected from halogen, hydroxyl, methoxy and ethoxy).8. A method of treating cystic fibrosis in a patient in need thereof,comprising: administering to the patient an effective amount of acompound selected from the group consisting of:

and pharmaceutically acceptable salts thereof; and administering acystic fibrosis transmembrane conductance regulator (CFTR) potentiatorand/or CFTR corrector.
 9. The method of claim 1, wherein the patient hasa ΔF508 mutant gene.
 10. The method claim 1, wherein the patient has ahomozygote mutation selected from the group consisting of: ΔF508/ΔF508or R117H/R117H.
 11. The method of claim 1, wherein the patient has aheterozygote mutation selected from the group consisting of:ΔF508/G551D; ΔF508/A455E; ΔF508/ G542X; Δ508F/W1204X; R553X/W1316X;W1282X/N1303K; F508D/R117H; N1303K/ 3849+10kbC>T; ΔF508/R334W;ΔF508/G178R and 591Δ18/ E831X.
 12. The method of claim 1, wherein thepatient has one or more mutations in the CFTR gene, wherein themutations are each selected from the group consisting of: G1244E,G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, G970R and R117H. 13.The method of claim 1, wherein the patient has one copy of a F508delmutation and a second mutation that results in a gating defect in theCFTR protein.
 14. The method of claim 13, wherein the patient isheterozygous for F508del and G551D CFTR mutation.
 15. The method ofclaim 1, wherein the patient has one copy of a F508del mutation and asecond mutation that results in residual CFTR activity.
 16. The methodof claim 15, wherein the patient has one copy of the F508del mutationand a second mutation that results in residual CFTR protein.
 17. Themethod of claim 1, wherein the patient is human.
 18. The method of claim1, comprising: administering to the patient an effective amount of thecompound; and administering ivacaftor.
 19. The method of claim 18,further comprising administering one or more of a compound selected fromthe group consisting of VX-661, VX-152, VX-440, VX-371, and lumacaftor.20. A method of treating a patient with F508del homozygous CFTRmutation, comprising: administering to the patient an effective amountof a compound of claim 1; administering ivacaftor; and administeringlumacaftor or VX661.
 21. A method of treating a patient with a A455EClass V or A455E/F508del CFTR mutation, comprising: administering to thepatient an effective amount of a compound of claim 1; administeringivacaftor; and administering a CFTR corrector selected from VX-661 andlumacaftor.
 22. A method of treating a patient with a G551D Class III orG551D/F508del CFTR mutation, comprising: administering to the patient aneffective amount of a compound of claim 1; administering ivacaftor; andoptionally administering a CFTR corrector selected from VX-661 andlumacaftor.
 23. A method of treating a patient with 3849 +10kb C>T/N1303CFTR mutations, comprising: administering to the patient an effectiveamount of a compound of claim 1; and optionally administering ivacaftor.